critical cases in case study

CritCases is a collaboration between Dr. Mike Betzner , director of STARS air ambulance service and EM Cases.

There are many approaches and therapeutic options in critical care that do not have a strong evidence base to guide us. We use our clinical judgement, gestalt and basic principles to make rapid decisions. This blog explores therapeutic options to various challenging critical care scenarios through an interactive case-based, Q&A framework. The case unfolds in a step-wise manner, as it would in real practice, and integrates opinions from critical care providers, not only from STARS, but from around the world. Each blog includes an open peer review from an expert on the given topic. Welcome to CritCases!

Crit Cases 14 Bronchopleural Fistula Management

Dr. Mike Misch guides us through this part 2 of a blunt chest trauma case with a presumed bronchopulmonary fistula requiring 3 chest tubes and describes options to optimize one-lung ventilation for safe transport...

CritCases 13 Shock and Hypoxia in Blunt Chest Trauma

In this CritCases blog, Shock and Hypoxia in Blunt Chest Trauma, a collaboration between STARS Air Ambulance Service, Mike Betzner and EM Cases, Mike Misch guides us through a hairy thoracic trauma case, reviewing principles of trauma resuscitation, airway considerations, tension pneumothorax management and a rare and challenging trauma diagnosis...

CritCases 12 Accidental Hypothermia and Cardiac Arrest

In this CritCases blog Michael Misch takes us through a case of accidental hypothermia and cardiac arrest, reviewing the controversies in management as well as the guidelines for rewarming, the role of ECMO and the alterations to ACLS cardiac arrest medications, CPR and defibrillations...

CritCases 11 LVAD Management in the GI Bleed Patient

In this CritCases blog Mike Misch presents a case of a patient with a left ventricular assist device (LVAD) with a postoperative acute lower GI bleed and answers practical questions such as:  How do you measure blood pressure in a patient with an LVAD? What are the common complications of LVADs that we must be aware of? What information can the LVAD controller provide? Why are LVAD patients at high risk for bleeding? and many more...

CritCases 10 Hyponatremia Associated Seizures

In this EM Cases CritCases blog - a collaboration between STARS Air Ambulance Service, Mike Betzner and EM Cases, a middle aged woman presents to a rural ED with headache and vomiting, normal vital signs with subsequent status epilepticus and serum sodium of 110 mmol/L. What management recommendations would you make to the rural ED physician, the transport team and in your ED with regards to treatment of seizures, safe correction of hyponatremia, airway management, search for underlying cause and prevention of Osmotic Demyelenation Syndrome?

CritCases 9 Pre-Eclampsia and Preterm Labor – Time Sensitive Management

In this CritCases blog we present a case of a 30 week gestational age pregnant woman with high blood pressure, headache, blurry vision and pelvic cramping. We discuss the management challenges of transporting a patient with severe pre-eclampsia and preterm labor, with special attention to dosing of magnesium, antihypertensive agents choice, and indications for steroids, tocolytics and antibiotics.

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Massive Pulmonary Embolism

Claire L. Keating, M.D.

Jennifer A. Cunningham, M.D.

Columbia University College of Physicians and Surgeons

HISTORY: 55-year-old female nursing home resident with past medical history of AIDS, dilated cardiomyopathy (estimated left ventricular ejection fraction 15% on a previous transthoracic echocardiogram), and prior deep venous thrombosis (DVT) was found to be hypotensive and in respiratory distress while at her skilled nursing facility.

She was brought to the emergency department, where vital signs were notable for temperature of 100.9ºF, HR=142/min, BP=90/60 mmHg after intravenous fluids, with oxygen saturation of 99% while breathing 100% oxygen via non-rebreather mask. Computed tomography of the chest with pulmonary angiogram protocol (Figure 1) revealed large, thrombi in the right main and left main pulmonary arteries with incomplete occlusion, in addition to multiple segmental thrombi in right upper, middle and lower lobes. No lower extremity deep vein thromboses were noted on venogram.  Anticoagulation was initiated and the patient was transferred to the intensive care unit (ICU) for further management.

FIGURE 1:   CT scan of the chest demonstrating pulmonary emboli in bilateral main pulmonary artery

What distinguishes massive from submassive pulmonary embolism?

• the presence of hypoxemia
• the presence of right ventricular dysfunction
• the presence of shock
• the presence of pulmonary hypertension
• the presence of concurrent deep venous thrombosis

Answer to Question 1

Correct answer: C

The main criteria defining a massive pulmonary embolism are signs of hemodynamic compromise [1]. These include:

-Arterial hypotension defined as systolic arterial blood pressure <90mmHg or a drop in systolic arterial blood pressure of at least 40mmHg for at least 15 minutes (mortality 15%) -Cardiogenic shock as manifested by tissue hypoperfusion and hypoxia, altered level of consciousness, oliguria, or cool, clammy extremities (mortality 25%) -Circulatory collapse requiring cardiopulmonary resuscitation (mortality 65%)

Patients with submassive pulmonary emboli are normotensive with signs of right ventricular dysfunction present (see below).

PAST MEDICAL HISTORY: AIDS (CD4+ cell count=20/mm3) Multiple cerebrovascular infarcts with residual expressive aphasia and hemiparesis Dilated cardiomyopathy (presumed HIV-related) Hypertension Chronic kidney disease with baseline serum creatinine of 1.5 mg/dL Past DVT (not on anticoagulation for unclear reasons)

MEDICATIONS: Clopidogrel ASA Enalapril Furosemide Levetiracetam Abacavir Lamivudine Zidovudine Efavirenz

PHYSICAL EXAM: Upon admission to ICU Vitals:  T=100.1ºF,  HR=112/min, BP=91/63 mmHg,  RR=28/min, SpO2=96% on 100% oxygen via nonrebreather mask General: awake, nonverbal, dyspneic and diaphoretic HEENT: Eyes deviated left, pupils 3mm and reactive, JVP estimated at 8cm H2O Heart: tachycardic, regular with frequent ectopy, grade 3/6 holosystolic murmur and S3 gallop present, point of maximal impulse displaced laterally Lungs: coarse breath sounds bilaterally Abdomen: soft, nontender, hypoactive bowel sounds, pulsatile liver, brown guaiac negative stool Extremities: right upper extremity with decreased tone, 1+ edema in lower extremities bilaterally, all extremities cool to touch Neurologic: withdrawal to pain in all extremities, spontaneous eye opening, non-attentive, nonverbal and not following commands.

ADMISSION LABORATORY VALUES: White blood count   14,600/mm3 Hemoglobin   10.6 g/dL Platelets   125,000/ mm3

Sodium   134 mmol/L Potassium   4.6 mmol/L Chloride   107 mmol/L Bicarbonate   13 mmol/L Blood urea nitrogen   45 mg/dL Creatinine   2.8 mg/dL (baseline 1.5) Serum glucose   102 mg/dL Troponin  2.7 ng/mL (upper limit normal = 0.08) BNP  1,944 pg/mL (upper limit normal = 100-400)

Arterial Blood Gases: Emergency Room (on 100% oxygen via non-rebreather mask): pH=7.32 PaCO2=25 mmHg PaO2=250 mmHg

ICU (prior to intubation, on 100% oxygen via non-rebreather mask): pH=7.04 PaCO2=38 mmHg PaO2=71 mmHg

 What echocardiogram findings are seen in submassive and massive pulmonary embolism?

• right ventricular dilation
• right ventricular hypokinesis with sparing of the right ventricular apex (McConnell sign)
• loss of inspiratory collapse on inferior vena cava
• paradoxical septal wall motion
• all of the above

Answer to Question 2

Correct answer: E

Doppler echocardiogram can be useful in supporting the diagnosis of submassive and massive pulmonary embolism, especially in the cases where a contrast chest CT cannot be performed immediately.  Findings on Doppler echocardiogram demonstrate acute right ventricular pressure overload in the absence of left ventricular or mitral valve disease with or without increased pulmonary artery pressures.  These findings typically occur only after >30% of the pulmonary vascular cross-sectional area is impaired and include [2]:

• right ventricular dilatation (larger than the left ventricle from the apical or subcostal view) and hypertrophy (about 6 mm; normal <4mm)
• right pulmonary artery dilatation
• paradoxical septal wall motion (interventricular septum bulges towards the left ventricle)
• loss of inspiratory collapse of inferior vena cava
• elevated pulmonary artery systolic pressure as estimated by the gradient across the tricuspid valve
• small difference in LV area during diastole and systole (low cardiac output)
• patent foramen ovale

What is the preferred hemodynamic support for hypotension in massive pulmonary embolism?

• intravenous fluids
• norepinephrine
• inotropic agents, such as isoproteronol
• vasopressin
• intra-aortic balloon counter-pulsation device (IABP)

Answer to Question 3

Correct answer: B

Norepinephrine is the preferred agent for hemodynamic support in massive pulmonary embolism with hypotension. This is based on several studies using canine models of pulmonary embolism [4-6], where isoproterenol or norepinephrine were administered for hemodynamic support in acute pulmonary embolism. Success in achieving hemodynamic stability and improvement in ventricular wall function was higher in dogs receiving infusions of norepinephrine. The effect is hypothesized to be due to increased systemic pressures, resulting in improved coronary perfusion and improved right ventricular function.  In patients with less severe hypotension and more severe cardiac dysfunction, inotropic agents may be considered as an adjunct or alternative to norepinephrine [6-11]. Newer inotropic agents, such as amrinone, which act as both inotropic agent and pulmonary vasodilator have shown promise in animal studies and case reports [12,13].

A number of detrimental effects of intravenous fluids have been documented in animal studies, including decreased cardiac output and diminished right coronary artery blood flow due to increased right ventricular dilation [4-9]. In the face of diminished right coronary artery flow, worsening right ventricular ischemia can lead to diminished RV systolic function, establishing a vicious cycle of auto-aggravation.  One study in humans [14], however, suggested that a 500 ml fluid load may initially improve cardiac output among patients with massive PE, although the long-term effects of fluid administration on cardiac function and hemodynamics are unclear.  Most authors would agree that intravenous fluids must be used with caution in patients with massive PE [15-17].

HOSPITAL COURSE After admission to the ICU, the patient received an intravenous infusion of unfractionated heparin drip and an intravenous infusion of norepinephrine at 5 micrograms/minute for hemodynamic support. A Foley catheter was placed with urine output remaining <0.5 mL/kg/hour despite a trial of intravenous fluid resuscitation.  Bedside transthoracic echocardiogram was performed and demonstrated a dilated left ventricle with depressed systolic function with an estimated left ventricular ejection fraction of 15% (unchanged from baseline echo), in addition to a new finding of  moderate right ventricular and right atrial dilatation with a calculated RV systolic pressure of 58mmHg (increased RV dysfunction from the prior study). There was moderate tricuspid regurgitation and a dilated inferior vena cava noted.  Consideration was given to systemic thrombolysis due to the presence of persistent hypotension and end organ dysfunction, however, with a therapeutic partial thromboplastin time (PTT) on heparin, massive hemoptysis (>250 cc with >2g/dL hemoglobin drop­) developed.  The trachea was urgently intubated and heparin was discontinued.  Interventional radiology was consulted for catheter thrombectomy and inferior vena caval (IVC) filter placement.

In cases of massive pulmonary embolism, what options remain when systemic thrombolysis cannot be performed safely?

• surgical embolectomy
• catheter-directed thrombolysis
• percutaneous embolectomy
• percutaneous thrombus fragmentation

Answer to Question 4

Correct answer:  E

Surgical embolectomy: Surgical embolectomy involves transection of the main pulmonary artery via sternotomy incision with manual extraction of thromboembolism.  Although in the past, peri-operative mortality was a high as 57%, some experienced centers now report peri-operative mortality of approximately 6% [33].  However, with the use of cardiopulmonary bypass and increasing surgical expertise, mortality and morbidity from surgical embolectomy can be minimized,[18,19] and may offer benefit particularly to those patients with evidence of pulmonary hypertension [18].

Historically, surgical embolectomy was the only available option for patients who fail or who have contraindications to systemic thrombolysis.  It is not clear what role it will play in the future given the advent of other interventional options (listed below). 

Catheter-directed thrombolysis: This technique requires placement of an intra-arterial catheter to the site of the embolus with bolus and infusion of a thrombolytic agent [20]. Catheter-directed thrombolysis usually requires concurrent intravenous unfractionated heparin administration.

Small studies, including case series and controlled trials, have evaluated the efficacy of intrapulmonary thrombolysis [21-23]. Although clinical endpoints such as mortality were not evaluated, these studies suggest equivalent or superior radiographic resolution of thrombolysis compared to systemic thrombolysis.  Bleeding complication rates were low following intrapulmonary thrombolysis, suggesting that catheter-directed thrombolysis may be possible even in patients who have contraindications to systemic thrombolysis [29]. It is noteworthy, however, that these regimens also utilized systemic anticoagulation.  Therefore, caution must be exercised in extrapolating the results of these small studies to patients with contraindications to systemic thrombolysis or anticoagulation.  Further investigation into the safety of this technique in high risk patient populations is needed.

Percutaneous aspiration thrombectomy or fragmentation: When systemic or intrapulmonary thrombolysis and surgical embolectomy are not possible, there are a number of interventional options available that aim to rapidly relieve central obstruction and restore hemodynamic stability [20]. 

Greenfield embolectomy catheter [20] :   This catheter (Boston Scientific/Meditech; Watertown, MA) is inserted into the site of the thrombus, and with manual suction using a large syringe retrieves the clot, which is then removed en bloc through the venotomy site or vascular sheath.

Rotatable pigtail catheter [20] :   The pigtail tip of this catheter (Cook Europe; Bjaeverskov, Denmark) is rotated either by hand or by an attachable low-speed electric catheter to disrupt the intrapulmonary clot into smaller fragments which then migrate into the distal pulmonary circulation. The catheter can be advanced into peripheral pulmonary branches and manually rotated to further clot fragmentation.

Rheolytic thrombectomy catheters [20] :   The Angiojet system (Possis; Minneapolis, MN) uses the Venturi effect to perform thrombectomy. This is a double lumen catheter, of which the inner smaller catheter directs a high-velocity stream of saline. The high-pressure generated by the smaller lumen catheter creates a low pressure state in the larger catheter resulting in a vortex and promotion of fragmentation and aspiration of the thrombus.

What are the most recent American College of Chest Physicians (ACCP) guidelines on placement of IVC filters in pulmonary embolism?

• routine use of retrievable IVC filter in patients with PE
• use of IVC filter among patients with a contraindication to anticoagulation
• use of IVC filter among patients with recurrent PE despite adequate anticoagulation

Answer to Question 5

Correct answer: D

The official recommendation from the 7th ACCP conference on Antithrombotic and Thrombolytic Therapy [30] is as follows: “In pulmonary embolism patients with a contraindication for, or a complication of anticoagulant therapy as well in those with recurrent thromboembolism despite adequate anticoagulation, we suggest placement of an IVC filter.”

Although this received only a Grade 2C recommendation (with low or very low evidence), there is general consensus within the pulmonary community that a patient at high risk for death due to recurrent pulmonary embolism may also benefit from placement of an IVC filter. This is based on a clinical trial of 400 patients with known deep vein thrombosis (with or without concomitant pulmonary embolism) randomized to IVC filter placement or anticoagulation alone. Concurrent placement of an IVC filter lowered the rate of new pulmonary embolism at day 12.   There was no difference in PE rates at 2 years, although there was a higher incidence of DVT in the IVC filter group [31]. Although there was no difference in short-term mortality observed, patients with massive PE were not included in this study.  Therefore, the use of a retrievable IVC filter [32] is a reasonable option among patients with severe hemodynamic compromise due to PE to prevent a recurrent catastrophic thromboembolism.

The patient required mechanically-assisted ventilation with a fraction of inspired oxygen (FiO2) of 0.6 and positive end-expiratory pressure (PEEP) of 10 cmH20 to maintain the arterial oxygen saturation >90%. Due to persistent hypotension after a trial of fluid resuscitation, norepinephrine was continued.  A trial infusion of dobutamine was limited by prolonged runs of non-sustained ventricular tachycardia (NSVT). The patient’s urine output remained minimal. Interventional radiology placed an IVC filter but declined to perform a catheter thrombectomy due to the patient’s baseline depressed cardiac function.  

Norepinephrine was discontinued by ICU day 6 and the patient’s oxygenation slowly improved, and mechanical ventilation was successfully discontinued on ICU day 8. Renal function improved without need for dialysis.  Heparin was reintroduced before patient was discharged from the ICU without recurrence of hemoptysis.  The patient recovered to her baseline status and was discharged on hospital day 39.

REFERENCES:

1.  Kucher N and Goldhaber SZ. Management of massive pulmonary embolism. Circulation 2005; 112:  e28-e32.

2.  Goldhaber SZ. Echocardiography in the management of pulmonary embolism.  Ann Intern Med 2002; 136:  691–700.

3.  Kasper W et al .  Distinguishing between acute and subacute massive pulmonary embolism by conventional and Doppler echocardiography. Br. Heart J . 1993; 70:  352-6.

4.  Molloy WD et al.  Treatment of shock in a canine model of pulmonary embolism.  Am Rev Respir Dis 1984; 130:  870-4.

5.  Rosenberg JC et al.  Isoproterenol and norepinephrine therapy for pulmonary embolism shock.  J Thorac Cardiovasc Surg 1971; 62:  144-58.

6.  Imamoto  et al.  Treatment of canine acute pulmonary embolic shock – effects of isoproterenol and norepinephrine on hemodynamics and ventricular wall motion.  Jpn Circ J 1990; 54:  1246-57.

7.   Manier G and Castaing Y.  Influence of cardiac output on oxygen exchange in acute pulmonary embolism.  Am Rev Respir Dis 1992; 145:  130-6.

8.  Ducas J et al.  Pulmonary vascular pressure-flow characteristics.  Effects of dopamine before and after pulmonary embolism.  Am Rev Respir Dis 1992; 145:  307-12.

 9.  Ghigone M et al.  Volume expansion versus norepinephrine in treatment of a low cardiac output complicating an acute increase in right ventricular afterload in dogs.  Anesthesiology 1984; 60:  132-5.

10.  Jardin F et al. Dobutamine: a hemodynamic evaluation in pulmonary embolism shock.  Crit Care Med 1985; 13:  1009-12.

11.  Prewitt RM.  Hemodynamic management in pulmonary embolism and acute hypoxemic respiratory failure.  Crit Care Med 1990; 18:  S61-9.

12.  Wolfe MW et al.  Hemodynamic effects of amrinone in a canine model of massive pulmonary embolism.  Chest 1992; 102:  274-8.

13.  Spence TH et al.  Pulmonary embolism:  improvement in hemodynamic function with amrinone therapy.  South Med J 1989; 82:  1267-8.

14.  Mercat A et al.  Hemodynamic effects of fluid loading in acute massive pulmonary embolism.   Crit Care Med 1999; 11:  339-45.

 15.  Piazza G and Goldhaber SZ.  The acutely decompensated right ventricle.  Chest 2005; 128:  1836-52.

16.  Mebazaa A et al.  Acute right ventricular failure – from pathophysiology to new treatments.  Intensive Care Med 2004; 30:  185-96.

17.  Layish DT and Tapson VF.  Pharmacologic hemodynamic support in massive pulmonary embolism.  Chest 1997; 111:  218-24.

18.  Jamieson SW et al.  Experience and results of 150 pulmonary thromboendarterectomy operations over a 29 month period.   J Thorac Cardiovasc Surg 1993; 106:  116-27.

19.  Gulba DC et al.  Medical compared with surgical treatment for massive pulmonary embolism.   Lancet 1994; 114:  576-7.

20.  Uflacker, R. Interventional Therapy for Pulmonary Embolism . J Vasc Interv Radiol. 2001; 12:147-164

21.  Gonzalez-Juanatey J et al.  Treatment of massive pulmonary thromboembolism with low intrapulmonary dosages of urokinase.  Chest 1992; 102:  341-6.

22.  Verstaete M et al.  Intravenous and intrapulmonary recombinant tissue-type plasminogen activator in the treatment of acute massive pulmonary embolism.   Circulation 1998; 77:  353-60.

23.  McCotter CJ et al.  Intrapulmonary artery infusion of urokinase for treatment of massive pulmonary embolism:  a review of 26 patients with and without contraindications to systemic thrombolytic therapy.  Clin Cardiol 1999; 22:  661-4.

24.  Kucher, N.  Catheter embolectomy for acute pulmonary embolism .  Chest 2007; 132:  657-663.

25.  Greenfield LJ et al.  Long-term experience with transvenous catheter pulmonary embolectomy.  J Vasc Surg 1993; 18:  450-8.

26.  Murphy JM et al.  Percutaneous catheter and guidewire fragmentation with local administration of recombinant tissue plasminogen activator as a treatment for massive pulmonary embolism.   Eur Radiol 1999; 9:  959-64.

27.  Stock KW et al.  Massive pulmonary embolism:  treatment with thrombus fragmentation and local fibrinolysis with recombinant human-tissue plasminogen activator.  Cardiovasc Intervent Radiol 1997; 20:  364-8.

28.  Schmitz-Rode T et al.  Fragmentation of massive pulmonary embolism using a pigtail rotation catheter.   Chest 1998; 114:  1427-36.

29.  Cela MC et al.  Nonsurgical pulmonary embolectomy.  In :  Cope C, ed. Current Techniques in Interventional Radiology.  Philadelphia:  Current Medicine, 1994; 12:  2-8.

30.  Buller HR et al. Antithrombotic therapy for venous thromboembolic disease: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004;  126(3 Suppl):401S-428S.

31.  Decousus H. et al . A clinical trial of vena caval filters in the prevention of pulmonary embolism in patients with proximal deep-vein thrombosis. N Engl J Med. 1998; 338(7):409-15.

32. Mismetti P et al.  A prospective long-term study of 220 patients with a retrievable vena cava filter for secondary prevention of venous thromboembolism.  Chest 2007; 131:  223-9.

33. Leacche M et al. Modern surgical treatment of massive pulmonary embolism: results in 47 consecutive patients after rapid diagnosis and aggressive surgical approach. J Thorac Cardiovasc Surg 2005; 129:1018-23.

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Methodology or method? A critical review of qualitative case study reports

Despite on-going debate about credibility, and reported limitations in comparison to other approaches, case study is an increasingly popular approach among qualitative researchers. We critically analysed the methodological descriptions of published case studies. Three high-impact qualitative methods journals were searched to locate case studies published in the past 5 years; 34 were selected for analysis. Articles were categorized as health and health services ( n= 12), social sciences and anthropology ( n= 7), or methods ( n= 15) case studies. The articles were reviewed using an adapted version of established criteria to determine whether adequate methodological justification was present, and if study aims, methods, and reported findings were consistent with a qualitative case study approach. Findings were grouped into five themes outlining key methodological issues: case study methodology or method, case of something particular and case selection, contextually bound case study, researcher and case interactions and triangulation, and study design inconsistent with methodology reported. Improved reporting of case studies by qualitative researchers will advance the methodology for the benefit of researchers and practitioners.

Case study research is an increasingly popular approach among qualitative researchers (Thomas, 2011 ). Several prominent authors have contributed to methodological developments, which has increased the popularity of case study approaches across disciplines (Creswell, 2013b ; Denzin & Lincoln, 2011b ; Merriam, 2009 ; Ragin & Becker, 1992 ; Stake, 1995 ; Yin, 2009 ). Current qualitative case study approaches are shaped by paradigm, study design, and selection of methods, and, as a result, case studies in the published literature vary. Differences between published case studies can make it difficult for researchers to define and understand case study as a methodology.

Experienced qualitative researchers have identified case study research as a stand-alone qualitative approach (Denzin & Lincoln, 2011b ). Case study research has a level of flexibility that is not readily offered by other qualitative approaches such as grounded theory or phenomenology. Case studies are designed to suit the case and research question and published case studies demonstrate wide diversity in study design. There are two popular case study approaches in qualitative research. The first, proposed by Stake ( 1995 ) and Merriam ( 2009 ), is situated in a social constructivist paradigm, whereas the second, by Yin ( 2012 ), Flyvbjerg ( 2011 ), and Eisenhardt ( 1989 ), approaches case study from a post-positivist viewpoint. Scholarship from both schools of inquiry has contributed to the popularity of case study and development of theoretical frameworks and principles that characterize the methodology.

The diversity of case studies reported in the published literature, and on-going debates about credibility and the use of case study in qualitative research practice, suggests that differences in perspectives on case study methodology may prevent researchers from developing a mutual understanding of practice and rigour. In addition, discussion about case study limitations has led some authors to query whether case study is indeed a methodology (Luck, Jackson, & Usher, 2006 ; Meyer, 2001 ; Thomas, 2010 ; Tight, 2010 ). Methodological discussion of qualitative case study research is timely, and a review is required to analyse and understand how this methodology is applied in the qualitative research literature. The aims of this study were to review methodological descriptions of published qualitative case studies, to review how the case study methodological approach was applied, and to identify issues that need to be addressed by researchers, editors, and reviewers. An outline of the current definitions of case study and an overview of the issues proposed in the qualitative methodological literature are provided to set the scene for the review.

Definitions of qualitative case study research

Case study research is an investigation and analysis of a single or collective case, intended to capture the complexity of the object of study (Stake, 1995 ). Qualitative case study research, as described by Stake ( 1995 ), draws together “naturalistic, holistic, ethnographic, phenomenological, and biographic research methods” in a bricoleur design, or in his words, “a palette of methods” (Stake, 1995 , pp. xi–xii). Case study methodology maintains deep connections to core values and intentions and is “particularistic, descriptive and heuristic” (Merriam, 2009 , p. 46).

As a study design, case study is defined by interest in individual cases rather than the methods of inquiry used. The selection of methods is informed by researcher and case intuition and makes use of naturally occurring sources of knowledge, such as people or observations of interactions that occur in the physical space (Stake, 1998 ). Thomas ( 2011 ) suggested that “analytical eclecticism” is a defining factor (p. 512). Multiple data collection and analysis methods are adopted to further develop and understand the case, shaped by context and emergent data (Stake, 1995 ). This qualitative approach “explores a real-life, contemporary bounded system (a case ) or multiple bounded systems (cases) over time, through detailed, in-depth data collection involving multiple sources of information … and reports a case description and case themes ” (Creswell, 2013b , p. 97). Case study research has been defined by the unit of analysis, the process of study, and the outcome or end product, all essentially the case (Merriam, 2009 ).

The case is an object to be studied for an identified reason that is peculiar or particular. Classification of the case and case selection procedures informs development of the study design and clarifies the research question. Stake ( 1995 ) proposed three types of cases and study design frameworks. These include the intrinsic case, the instrumental case, and the collective instrumental case. The intrinsic case is used to understand the particulars of a single case, rather than what it represents. An instrumental case study provides insight on an issue or is used to refine theory. The case is selected to advance understanding of the object of interest. A collective refers to an instrumental case which is studied as multiple, nested cases, observed in unison, parallel, or sequential order. More than one case can be simultaneously studied; however, each case study is a concentrated, single inquiry, studied holistically in its own entirety (Stake, 1995 , 1998 ).

Researchers who use case study are urged to seek out what is common and what is particular about the case. This involves careful and in-depth consideration of the nature of the case, historical background, physical setting, and other institutional and political contextual factors (Stake, 1998 ). An interpretive or social constructivist approach to qualitative case study research supports a transactional method of inquiry, where the researcher has a personal interaction with the case. The case is developed in a relationship between the researcher and informants, and presented to engage the reader, inviting them to join in this interaction and in case discovery (Stake, 1995 ). A postpositivist approach to case study involves developing a clear case study protocol with careful consideration of validity and potential bias, which might involve an exploratory or pilot phase, and ensures that all elements of the case are measured and adequately described (Yin, 2009 , 2012 ).

Current methodological issues in qualitative case study research

The future of qualitative research will be influenced and constructed by the way research is conducted, and by what is reviewed and published in academic journals (Morse, 2011 ). If case study research is to further develop as a principal qualitative methodological approach, and make a valued contribution to the field of qualitative inquiry, issues related to methodological credibility must be considered. Researchers are required to demonstrate rigour through adequate descriptions of methodological foundations. Case studies published without sufficient detail for the reader to understand the study design, and without rationale for key methodological decisions, may lead to research being interpreted as lacking in quality or credibility (Hallberg, 2013 ; Morse, 2011 ).

There is a level of artistic license that is embraced by qualitative researchers and distinguishes practice, which nurtures creativity, innovation, and reflexivity (Denzin & Lincoln, 2011b ; Morse, 2009 ). Qualitative research is “inherently multimethod” (Denzin & Lincoln, 2011a , p. 5); however, with this creative freedom, it is important for researchers to provide adequate description for methodological justification (Meyer, 2001 ). This includes paradigm and theoretical perspectives that have influenced study design. Without adequate description, study design might not be understood by the reader, and can appear to be dishonest or inaccurate. Reviewers and readers might be confused by the inconsistent or inappropriate terms used to describe case study research approach and methods, and be distracted from important study findings (Sandelowski, 2000 ). This issue extends beyond case study research, and others have noted inconsistencies in reporting of methodology and method by qualitative researchers. Sandelowski ( 2000 , 2010 ) argued for accurate identification of qualitative description as a research approach. She recommended that the selected methodology should be harmonious with the study design, and be reflected in methods and analysis techniques. Similarly, Webb and Kevern ( 2000 ) uncovered inconsistencies in qualitative nursing research with focus group methods, recommending that methodological procedures must cite seminal authors and be applied with respect to the selected theoretical framework. Incorrect labelling using case study might stem from the flexibility in case study design and non-directional character relative to other approaches (Rosenberg & Yates, 2007 ). Methodological integrity is required in design of qualitative studies, including case study, to ensure study rigour and to enhance credibility of the field (Morse, 2011 ).

Case study has been unnecessarily devalued by comparisons with statistical methods (Eisenhardt, 1989 ; Flyvbjerg, 2006 , 2011 ; Jensen & Rodgers, 2001 ; Piekkari, Welch, & Paavilainen, 2009 ; Tight, 2010 ; Yin, 1999 ). It is reputed to be the “the weak sibling” in comparison to other, more rigorous, approaches (Yin, 2009 , p. xiii). Case study is not an inherently comparative approach to research. The objective is not statistical research, and the aim is not to produce outcomes that are generalizable to all populations (Thomas, 2011 ). Comparisons between case study and statistical research do little to advance this qualitative approach, and fail to recognize its inherent value, which can be better understood from the interpretive or social constructionist viewpoint of other authors (Merriam, 2009 ; Stake, 1995 ). Building on discussions relating to “fuzzy” (Bassey, 2001 ), or naturalistic generalizations (Stake, 1978 ), or transference of concepts and theories (Ayres, Kavanaugh, & Knafl, 2003 ; Morse et al., 2011 ) would have more relevance.

Case study research has been used as a catch-all design to justify or add weight to fundamental qualitative descriptive studies that do not fit with other traditional frameworks (Merriam, 2009 ). A case study has been a “convenient label for our research—when we ‘can't think of anything ‘better”—in an attempt to give it [qualitative methodology] some added respectability” (Tight, 2010 , p. 337). Qualitative case study research is a pliable approach (Merriam, 2009 ; Meyer, 2001 ; Stake, 1995 ), and has been likened to a “curious methodological limbo” (Gerring, 2004 , p. 341) or “paradigmatic bridge” (Luck et al., 2006 , p. 104), that is on the borderline between postpositivist and constructionist interpretations. This has resulted in inconsistency in application, which indicates that flexibility comes with limitations (Meyer, 2001 ), and the open nature of case study research might be off-putting to novice researchers (Thomas, 2011 ). The development of a well-(in)formed theoretical framework to guide a case study should improve consistency, rigour, and trust in studies published in qualitative research journals (Meyer, 2001 ).

Assessment of rigour

The purpose of this study was to analyse the methodological descriptions of case studies published in qualitative methods journals. To do this we needed to develop a suitable framework, which used existing, established criteria for appraising qualitative case study research rigour (Creswell, 2013b ; Merriam, 2009 ; Stake, 1995 ). A number of qualitative authors have developed concepts and criteria that are used to determine whether a study is rigorous (Denzin & Lincoln, 2011b ; Lincoln, 1995 ; Sandelowski & Barroso, 2002 ). The criteria proposed by Stake ( 1995 ) provide a framework for readers and reviewers to make judgements regarding case study quality, and identify key characteristics essential for good methodological rigour. Although each of the factors listed in Stake's criteria could enhance the quality of a qualitative research report, in Table I we present an adapted criteria used in this study, which integrates more recent work by Merriam ( 2009 ) and Creswell ( 2013b ). Stake's ( 1995 ) original criteria were separated into two categories. The first list of general criteria is “relevant for all qualitative research.” The second list, “high relevance to qualitative case study research,” was the criteria that we decided had higher relevance to case study research. This second list was the main criteria used to assess the methodological descriptions of the case studies reviewed. The complete table has been preserved so that the reader can determine how the original criteria were adapted.

Framework for assessing quality in qualitative case study research.

Adapted from Stake ( 1995 , p. 131).

Study design

The critical review method described by Grant and Booth ( 2009 ) was used, which is appropriate for the assessment of research quality, and is used for literature analysis to inform research and practice. This type of review goes beyond the mapping and description of scoping or rapid reviews, to include “analysis and conceptual innovation” (Grant & Booth, 2009 , p. 93). A critical review is used to develop existing, or produce new, hypotheses or models. This is different to systematic reviews that answer clinical questions. It is used to evaluate existing research and competing ideas, to provide a “launch pad” for conceptual development and “subsequent testing” (Grant & Booth, 2009 , p. 93).

Qualitative methods journals were located by a search of the 2011 ISI Journal Citation Reports in Social Science, via the database Web of Knowledge (see m.webofknowledge.com). No “qualitative research methods” category existed in the citation reports; therefore, a search of all categories was performed using the term “qualitative.” In Table II , we present the qualitative methods journals located, ranked by impact factor. The highest ranked journals were selected for searching. We acknowledge that the impact factor ranking system might not be the best measure of journal quality (Cheek, Garnham, & Quan, 2006 ); however, this was the most appropriate and accessible method available.

International Journal of Qualitative Studies on Health and Well-being.

Search strategy

In March 2013, searches of the journals, Qualitative Health Research , Qualitative Research , and Qualitative Inquiry were completed to retrieve studies with “case study” in the abstract field. The search was limited to the past 5 years (1 January 2008 to 1 March 2013). The objective was to locate published qualitative case studies suitable for assessment using the adapted criterion. Viewpoints, commentaries, and other article types were excluded from review. Title and abstracts of the 45 retrieved articles were read by the first author, who identified 34 empirical case studies for review. All authors reviewed the 34 studies to confirm selection and categorization. In Table III , we present the 34 case studies grouped by journal, and categorized by research topic, including health sciences, social sciences and anthropology, and methods research. There was a discrepancy in categorization of one article on pedagogy and a new teaching method published in Qualitative Inquiry (Jorrín-Abellán, Rubia-Avi, Anguita-Martínez, Gómez-Sánchez, & Martínez-Mones, 2008 ). Consensus was to allocate to the methods category.

Outcomes of search of qualitative methods journals.

In Table III , the number of studies located, and final numbers selected for review have been reported. Qualitative Health Research published the most empirical case studies ( n= 16). In the health category, there were 12 case studies of health conditions, health services, and health policy issues, all published in Qualitative Health Research . Seven case studies were categorized as social sciences and anthropology research, which combined case study with biography and ethnography methodologies. All three journals published case studies on methods research to illustrate a data collection or analysis technique, methodological procedure, or related issue.

The methodological descriptions of 34 case studies were critically reviewed using the adapted criteria. All articles reviewed contained a description of study methods; however, the length, amount of detail, and position of the description in the article varied. Few studies provided an accurate description and rationale for using a qualitative case study approach. In the 34 case studies reviewed, three described a theoretical framework informed by Stake ( 1995 ), two by Yin ( 2009 ), and three provided a mixed framework informed by various authors, which might have included both Yin and Stake. Few studies described their case study design, or included a rationale that explained why they excluded or added further procedures, and whether this was to enhance the study design, or to better suit the research question. In 26 of the studies no reference was provided to principal case study authors. From reviewing the description of methods, few authors provided a description or justification of case study methodology that demonstrated how their study was informed by the methodological literature that exists on this approach.

The methodological descriptions of each study were reviewed using the adapted criteria, and the following issues were identified: case study methodology or method; case of something particular and case selection; contextually bound case study; researcher and case interactions and triangulation; and, study design inconsistent with methodology. An outline of how the issues were developed from the critical review is provided, followed by a discussion of how these relate to the current methodological literature.

Case study methodology or method

A third of the case studies reviewed appeared to use a case report method, not case study methodology as described by principal authors (Creswell, 2013b ; Merriam, 2009 ; Stake, 1995 ; Yin, 2009 ). Case studies were identified as a case report because of missing methodological detail and by review of the study aims and purpose. These reports presented data for small samples of no more than three people, places or phenomenon. Four studies, or “case reports” were single cases selected retrospectively from larger studies (Bronken, Kirkevold, Martinsen, & Kvigne, 2012 ; Coltart & Henwood, 2012 ; Hooghe, Neimeyer, & Rober, 2012 ; Roscigno et al., 2012 ). Case reports were not a case of something, instead were a case demonstration or an example presented in a report. These reports presented outcomes, and reported on how the case could be generalized. Descriptions focussed on the phenomena, rather than the case itself, and did not appear to study the case in its entirety.

Case reports had minimal in-text references to case study methodology, and were informed by other qualitative traditions or secondary sources (Adamson & Holloway, 2012 ; Buzzanell & D'Enbeau, 2009 ; Nagar-Ron & Motzafi-Haller, 2011 ). This does not suggest that case study methodology cannot be multimethod, however, methodology should be consistent in design, be clearly described (Meyer, 2001 ; Stake, 1995 ), and maintain focus on the case (Creswell, 2013b ).

To demonstrate how case reports were identified, three examples are provided. The first, Yeh ( 2013 ) described their study as, “the examination of the emergence of vegetarianism in Victorian England serves as a case study to reveal the relationships between boundaries and entities” (p. 306). The findings were a historical case report, which resulted from an ethnographic study of vegetarianism. Cunsolo Willox, Harper, Edge, ‘My Word’: Storytelling and Digital Media Lab, and Rigolet Inuit Community Government (2013) used “a case study that illustrates the usage of digital storytelling within an Inuit community” (p. 130). This case study reported how digital storytelling can be used with indigenous communities as a participatory method to illuminate the benefits of this method for other studies. This “case study was conducted in the Inuit community” but did not include the Inuit community in case analysis (Cunsolo Willox et al., 2013 , p. 130). Bronken et al. ( 2012 ) provided a single case report to demonstrate issues observed in a larger clinical study of aphasia and stroke, without adequate case description or analysis.

Case study of something particular and case selection

Case selection is a precursor to case analysis, which needs to be presented as a convincing argument (Merriam, 2009 ). Descriptions of the case were often not adequate to ascertain why the case was selected, or whether it was a particular exemplar or outlier (Thomas, 2011 ). In a number of case studies in the health and social science categories, it was not explicit whether the case was of something particular, or peculiar to their discipline or field (Adamson & Holloway, 2012 ; Bronken et al., 2012 ; Colón-Emeric et al., 2010 ; Jackson, Botelho, Welch, Joseph, & Tennstedt, 2012 ; Mawn et al., 2010 ; Snyder-Young, 2011 ). There were exceptions in the methods category ( Table III ), where cases were selected by researchers to report on a new or innovative method. The cases emerged through heuristic study, and were reported to be particular, relative to the existing methods literature (Ajodhia-Andrews & Berman, 2009 ; Buckley & Waring, 2013 ; Cunsolo Willox et al., 2013 ; De Haene, Grietens, & Verschueren, 2010 ; Gratton & O'Donnell, 2011 ; Sumsion, 2013 ; Wimpenny & Savin-Baden, 2012 ).

Case selection processes were sometimes insufficient to understand why the case was selected from the global population of cases, or what study of this case would contribute to knowledge as compared with other possible cases (Adamson & Holloway, 2012 ; Bronken et al., 2012 ; Colón-Emeric et al., 2010 ; Jackson et al., 2012 ; Mawn et al., 2010 ). In two studies, local cases were selected (Barone, 2010 ; Fourie & Theron, 2012 ) because the researcher was familiar with and had access to the case. Possible limitations of a convenience sample were not acknowledged. Purposeful sampling was used to recruit participants within the case of one study, but not of the case itself (Gallagher et al., 2013 ). Random sampling was completed for case selection in two studies (Colón-Emeric et al., 2010 ; Jackson et al., 2012 ), which has limited meaning in interpretive qualitative research.

To demonstrate how researchers provided a good justification for the selection of case study approaches, four examples are provided. The first, cases of residential care homes, were selected because of reported occurrences of mistreatment, which included residents being locked in rooms at night (Rytterström, Unosson, & Arman, 2013 ). Roscigno et al. ( 2012 ) selected cases of parents who were admitted for early hospitalization in neonatal intensive care with a threatened preterm delivery before 26 weeks. Hooghe et al. ( 2012 ) used random sampling to select 20 couples that had experienced the death of a child; however, the case study was of one couple and a particular metaphor described only by them. The final example, Coltart and Henwood ( 2012 ), provided a detailed account of how they selected two cases from a sample of 46 fathers based on personal characteristics and beliefs. They described how the analysis of the two cases would contribute to their larger study on first time fathers and parenting.

Contextually bound case study

The limits or boundaries of the case are a defining factor of case study methodology (Merriam, 2009 ; Ragin & Becker, 1992 ; Stake, 1995 ; Yin, 2009 ). Adequate contextual description is required to understand the setting or context in which the case is revealed. In the health category, case studies were used to illustrate a clinical phenomenon or issue such as compliance and health behaviour (Colón-Emeric et al., 2010 ; D'Enbeau, Buzzanell, & Duckworth, 2010 ; Gallagher et al., 2013 ; Hooghe et al., 2012 ; Jackson et al., 2012 ; Roscigno et al., 2012 ). In these case studies, contextual boundaries, such as physical and institutional descriptions, were not sufficient to understand the case as a holistic system, for example, the general practitioner (GP) clinic in Gallagher et al. ( 2013 ), or the nursing home in Colón-Emeric et al. ( 2010 ). Similarly, in the social science and methods categories, attention was paid to some components of the case context, but not others, missing important information required to understand the case as a holistic system (Alexander, Moreira, & Kumar, 2012 ; Buzzanell & D'Enbeau, 2009 ; Nairn & Panelli, 2009 ; Wimpenny & Savin-Baden, 2012 ).

In two studies, vicarious experience or vignettes (Nairn & Panelli, 2009 ) and images (Jorrín-Abellán et al., 2008 ) were effective to support description of context, and might have been a useful addition for other case studies. Missing contextual boundaries suggests that the case might not be adequately defined. Additional information, such as the physical, institutional, political, and community context, would improve understanding of the case (Stake, 1998 ). In Boxes 1 and 2 , we present brief synopses of two studies that were reviewed, which demonstrated a well bounded case. In Box 1 , Ledderer ( 2011 ) used a qualitative case study design informed by Stake's tradition. In Box 2 , Gillard, Witt, and Watts ( 2011 ) were informed by Yin's tradition. By providing a brief outline of the case studies in Boxes 1 and 2 , we demonstrate how effective case boundaries can be constructed and reported, which may be of particular interest to prospective case study researchers.

Article synopsis of case study research using Stake's tradition

Ledderer ( 2011 ) used a qualitative case study research design, informed by modern ethnography. The study is bounded to 10 general practice clinics in Denmark, who had received federal funding to implement preventative care services based on a Motivational Interviewing intervention. The researcher question focussed on “why is it so difficult to create change in medical practice?” (Ledderer, 2011 , p. 27). The study context was adequately described, providing detail on the general practitioner (GP) clinics and relevant political and economic influences. Methodological decisions are described in first person narrative, providing insight on researcher perspectives and interaction with the case. Forty-four interviews were conducted, which focussed on how GPs conducted consultations, and the form, nature and content, rather than asking their opinion or experience (Ledderer, 2011 , p. 30). The duration and intensity of researcher immersion in the case enhanced depth of description and trustworthiness of study findings. Analysis was consistent with Stake's tradition, and the researcher provided examples of inquiry techniques used to challenge assumptions about emerging themes. Several other seminal qualitative works were cited. The themes and typology constructed are rich in narrative data and storytelling by clinic staff, demonstrating individual clinic experiences as well as shared meanings and understandings about changing from a biomedical to psychological approach to preventative health intervention. Conclusions make note of social and cultural meanings and lessons learned, which might not have been uncovered using a different methodology.

Article synopsis of case study research using Yin's tradition

Gillard et al. ( 2011 ) study of camps for adolescents living with HIV/AIDs provided a good example of Yin's interpretive case study approach. The context of the case is bounded by the three summer camps of which the researchers had prior professional involvement. A case study protocol was developed that used multiple methods to gather information at three data collection points coinciding with three youth camps (Teen Forum, Discover Camp, and Camp Strong). Gillard and colleagues followed Yin's ( 2009 ) principles, using a consistent data protocol that enhanced cross-case analysis. Data described the young people, the camp physical environment, camp schedule, objectives and outcomes, and the staff of three youth camps. The findings provided a detailed description of the context, with less detail of individual participants, including insight into researcher's interpretations and methodological decisions throughout the data collection and analysis process. Findings provided the reader with a sense of “being there,” and are discovered through constant comparison of the case with the research issues; the case is the unit of analysis. There is evidence of researcher immersion in the case, and Gillard reports spending significant time in the field in a naturalistic and integrated youth mentor role.

This case study is not intended to have a significant impact on broader health policy, although does have implications for health professionals working with adolescents. Study conclusions will inform future camps for young people with chronic disease, and practitioners are able to compare similarities between this case and their own practice (for knowledge translation). No limitations of this article were reported. Limitations related to publication of this case study were that it was 20 pages long and used three tables to provide sufficient description of the camp and program components, and relationships with the research issue.

Researcher and case interactions and triangulation

Researcher and case interactions and transactions are a defining feature of case study methodology (Stake, 1995 ). Narrative stories, vignettes, and thick description are used to provoke vicarious experience and a sense of being there with the researcher in their interaction with the case. Few of the case studies reviewed provided details of the researcher's relationship with the case, researcher–case interactions, and how these influenced the development of the case study (Buzzanell & D'Enbeau, 2009 ; D'Enbeau et al., 2010 ; Gallagher et al., 2013 ; Gillard et al., 2011 ; Ledderer, 2011 ; Nagar-Ron & Motzafi-Haller, 2011 ). The role and position of the researcher needed to be self-examined and understood by readers, to understand how this influenced interactions with participants, and to determine what triangulation is needed (Merriam, 2009 ; Stake, 1995 ).

Gillard et al. ( 2011 ) provided a good example of triangulation, comparing data sources in a table (p. 1513). Triangulation of sources was used to reveal as much depth as possible in the study by Nagar-Ron and Motzafi-Haller ( 2011 ), while also enhancing confirmation validity. There were several case studies that would have benefited from improved range and use of data sources, and descriptions of researcher–case interactions (Ajodhia-Andrews & Berman, 2009 ; Bronken et al., 2012 ; Fincham, Scourfield, & Langer, 2008 ; Fourie & Theron, 2012 ; Hooghe et al., 2012 ; Snyder-Young, 2011 ; Yeh, 2013 ).

Study design inconsistent with methodology

Good, rigorous case studies require a strong methodological justification (Meyer, 2001 ) and a logical and coherent argument that defines paradigm, methodological position, and selection of study methods (Denzin & Lincoln, 2011b ). Methodological justification was insufficient in several of the studies reviewed (Barone, 2010 ; Bronken et al., 2012 ; Hooghe et al., 2012 ; Mawn et al., 2010 ; Roscigno et al., 2012 ; Yeh, 2013 ). This was judged by the absence, or inadequate or inconsistent reference to case study methodology in-text.

In six studies, the methodological justification provided did not relate to case study. There were common issues identified. Secondary sources were used as primary methodological references indicating that study design might not have been theoretically sound (Colón-Emeric et al., 2010 ; Coltart & Henwood, 2012 ; Roscigno et al., 2012 ; Snyder-Young, 2011 ). Authors and sources cited in methodological descriptions were inconsistent with the actual study design and practices used (Fourie & Theron, 2012 ; Hooghe et al., 2012 ; Jorrín-Abellán et al., 2008 ; Mawn et al., 2010 ; Rytterström et al., 2013 ; Wimpenny & Savin-Baden, 2012 ). This occurred when researchers cited Stake or Yin, or both (Mawn et al., 2010 ; Rytterström et al., 2013 ), although did not follow their paradigmatic or methodological approach. In 26 studies there were no citations for a case study methodological approach.

The findings of this study have highlighted a number of issues for researchers. A considerable number of case studies reviewed were missing key elements that define qualitative case study methodology and the tradition cited. A significant number of studies did not provide a clear methodological description or justification relevant to case study. Case studies in health and social sciences did not provide sufficient information for the reader to understand case selection, and why this case was chosen above others. The context of the cases were not described in adequate detail to understand all relevant elements of the case context, which indicated that cases may have not been contextually bounded. There were inconsistencies between reported methodology, study design, and paradigmatic approach in case studies reviewed, which made it difficult to understand the study methodology and theoretical foundations. These issues have implications for methodological integrity and honesty when reporting study design, which are values of the qualitative research tradition and are ethical requirements (Wager & Kleinert, 2010a ). Poorly described methodological descriptions may lead the reader to misinterpret or discredit study findings, which limits the impact of the study, and, as a collective, hinders advancements in the broader qualitative research field.

The issues highlighted in our review build on current debates in the case study literature, and queries about the value of this methodology. Case study research can be situated within different paradigms or designed with an array of methods. In order to maintain the creativity and flexibility that is valued in this methodology, clearer descriptions of paradigm and theoretical position and methods should be provided so that study findings are not undervalued or discredited. Case study research is an interdisciplinary practice, which means that clear methodological descriptions might be more important for this approach than other methodologies that are predominantly driven by fewer disciplines (Creswell, 2013b ).

Authors frequently omit elements of methodologies and include others to strengthen study design, and we do not propose a rigid or purist ideology in this paper. On the contrary, we encourage new ideas about using case study, together with adequate reporting, which will advance the value and practice of case study. The implications of unclear methodological descriptions in the studies reviewed were that study design appeared to be inconsistent with reported methodology, and key elements required for making judgements of rigour were missing. It was not clear whether the deviations from methodological tradition were made by researchers to strengthen the study design, or because of misinterpretations. Morse ( 2011 ) recommended that innovations and deviations from practice are best made by experienced researchers, and that a novice might be unaware of the issues involved with making these changes. To perpetuate the tradition of case study research, applications in the published literature should have consistencies with traditional methodological constructions, and deviations should be described with a rationale that is inherent in study conduct and findings. Providing methodological descriptions that demonstrate a strong theoretical foundation and coherent study design will add credibility to the study, while ensuring the intrinsic meaning of case study is maintained.

The value of this review is that it contributes to discussion of whether case study is a methodology or method. We propose possible reasons why researchers might make this misinterpretation. Researchers may interchange the terms methods and methodology, and conduct research without adequate attention to epistemology and historical tradition (Carter & Little, 2007 ; Sandelowski, 2010 ). If the rich meaning that naming a qualitative methodology brings to the study is not recognized, a case study might appear to be inconsistent with the traditional approaches described by principal authors (Creswell, 2013a ; Merriam, 2009 ; Stake, 1995 ; Yin, 2009 ). If case studies are not methodologically and theoretically situated, then they might appear to be a case report.

Case reports are promoted by university and medical journals as a method of reporting on medical or scientific cases; guidelines for case reports are publicly available on websites ( http://www.hopkinsmedicine.org/institutional_review_board/guidelines_policies/guidelines/case_report.html ). The various case report guidelines provide a general criteria for case reports, which describes that this form of report does not meet the criteria of research, is used for retrospective analysis of up to three clinical cases, and is primarily illustrative and for educational purposes. Case reports can be published in academic journals, but do not require approval from a human research ethics committee. Traditionally, case reports describe a single case, to explain how and what occurred in a selected setting, for example, to illustrate a new phenomenon that has emerged from a larger study. A case report is not necessarily particular or the study of a case in its entirety, and the larger study would usually be guided by a different research methodology.

This description of a case report is similar to what was provided in some studies reviewed. This form of report lacks methodological grounding and qualities of research rigour. The case report has publication value in demonstrating an example and for dissemination of knowledge (Flanagan, 1999 ). However, case reports have different meaning and purpose to case study, which needs to be distinguished. Findings of our review suggest that the medical understanding of a case report has been confused with qualitative case study approaches.

In this review, a number of case studies did not have methodological descriptions that included key characteristics of case study listed in the adapted criteria, and several issues have been discussed. There have been calls for improvements in publication quality of qualitative research (Morse, 2011 ), and for improvements in peer review of submitted manuscripts (Carter & Little, 2007 ; Jasper, Vaismoradi, Bondas, & Turunen, 2013 ). The challenging nature of editor and reviewers responsibilities are acknowledged in the literature (Hames, 2013 ; Wager & Kleinert, 2010b ); however, review of case study methodology should be prioritized because of disputes on methodological value.

Authors using case study approaches are recommended to describe their theoretical framework and methods clearly, and to seek and follow specialist methodological advice when needed (Wager & Kleinert, 2010a ). Adequate page space for case study description would contribute to better publications (Gillard et al., 2011 ). Capitalizing on the ability to publish complementary resources should be considered.

Limitations of the review

There is a level of subjectivity involved in this type of review and this should be considered when interpreting study findings. Qualitative methods journals were selected because the aims and scope of these journals are to publish studies that contribute to methodological discussion and development of qualitative research. Generalist health and social science journals were excluded that might have contained good quality case studies. Journals in business or education were also excluded, although a review of case studies in international business journals has been published elsewhere (Piekkari et al., 2009 ).

The criteria used to assess the quality of the case studies were a set of qualitative indicators. A numerical or ranking system might have resulted in different results. Stake's ( 1995 ) criteria have been referenced elsewhere, and was deemed the best available (Creswell, 2013b ; Crowe et al., 2011 ). Not all qualitative studies are reported in a consistent way and some authors choose to report findings in a narrative form in comparison to a typical biomedical report style (Sandelowski & Barroso, 2002 ), if misinterpretations were made this may have affected the review.

Case study research is an increasingly popular approach among qualitative researchers, which provides methodological flexibility through the incorporation of different paradigmatic positions, study designs, and methods. However, whereas flexibility can be an advantage, a myriad of different interpretations has resulted in critics questioning the use of case study as a methodology. Using an adaptation of established criteria, we aimed to identify and assess the methodological descriptions of case studies in high impact, qualitative methods journals. Few articles were identified that applied qualitative case study approaches as described by experts in case study design. There were inconsistencies in methodology and study design, which indicated that researchers were confused whether case study was a methodology or a method. Commonly, there appeared to be confusion between case studies and case reports. Without clear understanding and application of the principles and key elements of case study methodology, there is a risk that the flexibility of the approach will result in haphazard reporting, and will limit its global application as a valuable, theoretically supported methodology that can be rigorously applied across disciplines and fields.

Conflict of interest and funding

The authors have not received any funding or benefits from industry or elsewhere to conduct this study.

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Organizing Your Social Sciences Research Assignments

• Annotated Bibliography
• Analyzing a Scholarly Journal Article
• Group Presentations
• Dealing with Nervousness
• Using Visual Aids
• Grading Someone Else's Paper
• Types of Structured Group Activities
• Group Project Survival Skills
• Leading a Class Discussion
• Multiple Book Review Essay
• Reviewing Collected Works
• Writing a Case Analysis Paper
• Writing a Case Study
• About Informed Consent
• Writing Field Notes
• Writing a Policy Memo
• Writing a Reflective Paper
• Writing a Research Proposal
• Generative AI and Writing
• Acknowledgments

A case study research paper examines a person, place, event, condition, phenomenon, or other type of subject of analysis in order to extrapolate  key themes and results that help predict future trends, illuminate previously hidden issues that can be applied to practice, and/or provide a means for understanding an important research problem with greater clarity. A case study research paper usually examines a single subject of analysis, but case study papers can also be designed as a comparative investigation that shows relationships between two or more subjects. The methods used to study a case can rest within a quantitative, qualitative, or mixed-method investigative paradigm.

Case Studies. Writing@CSU. Colorado State University; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010 ; “What is a Case Study?” In Swanborn, Peter G. Case Study Research: What, Why and How? London: SAGE, 2010.

How to Approach Writing a Case Study Research Paper

General information about how to choose a topic to investigate can be found under the " Choosing a Research Problem " tab in the Organizing Your Social Sciences Research Paper writing guide. Review this page because it may help you identify a subject of analysis that can be investigated using a case study design.

However, identifying a case to investigate involves more than choosing the research problem . A case study encompasses a problem contextualized around the application of in-depth analysis, interpretation, and discussion, often resulting in specific recommendations for action or for improving existing conditions. As Seawright and Gerring note, practical considerations such as time and access to information can influence case selection, but these issues should not be the sole factors used in describing the methodological justification for identifying a particular case to study. Given this, selecting a case includes considering the following:

• The case represents an unusual or atypical example of a research problem that requires more in-depth analysis? Cases often represent a topic that rests on the fringes of prior investigations because the case may provide new ways of understanding the research problem. For example, if the research problem is to identify strategies to improve policies that support girl's access to secondary education in predominantly Muslim nations, you could consider using Azerbaijan as a case study rather than selecting a more obvious nation in the Middle East. Doing so may reveal important new insights into recommending how governments in other predominantly Muslim nations can formulate policies that support improved access to education for girls.
• The case provides important insight or illuminate a previously hidden problem? In-depth analysis of a case can be based on the hypothesis that the case study will reveal trends or issues that have not been exposed in prior research or will reveal new and important implications for practice. For example, anecdotal evidence may suggest drug use among homeless veterans is related to their patterns of travel throughout the day. Assuming prior studies have not looked at individual travel choices as a way to study access to illicit drug use, a case study that observes a homeless veteran could reveal how issues of personal mobility choices facilitate regular access to illicit drugs. Note that it is important to conduct a thorough literature review to ensure that your assumption about the need to reveal new insights or previously hidden problems is valid and evidence-based.
• The case challenges and offers a counter-point to prevailing assumptions? Over time, research on any given topic can fall into a trap of developing assumptions based on outdated studies that are still applied to new or changing conditions or the idea that something should simply be accepted as "common sense," even though the issue has not been thoroughly tested in current practice. A case study analysis may offer an opportunity to gather evidence that challenges prevailing assumptions about a research problem and provide a new set of recommendations applied to practice that have not been tested previously. For example, perhaps there has been a long practice among scholars to apply a particular theory in explaining the relationship between two subjects of analysis. Your case could challenge this assumption by applying an innovative theoretical framework [perhaps borrowed from another discipline] to explore whether this approach offers new ways of understanding the research problem. Taking a contrarian stance is one of the most important ways that new knowledge and understanding develops from existing literature.
• The case provides an opportunity to pursue action leading to the resolution of a problem? Another way to think about choosing a case to study is to consider how the results from investigating a particular case may result in findings that reveal ways in which to resolve an existing or emerging problem. For example, studying the case of an unforeseen incident, such as a fatal accident at a railroad crossing, can reveal hidden issues that could be applied to preventative measures that contribute to reducing the chance of accidents in the future. In this example, a case study investigating the accident could lead to a better understanding of where to strategically locate additional signals at other railroad crossings so as to better warn drivers of an approaching train, particularly when visibility is hindered by heavy rain, fog, or at night.
• The case offers a new direction in future research? A case study can be used as a tool for an exploratory investigation that highlights the need for further research about the problem. A case can be used when there are few studies that help predict an outcome or that establish a clear understanding about how best to proceed in addressing a problem. For example, after conducting a thorough literature review [very important!], you discover that little research exists showing the ways in which women contribute to promoting water conservation in rural communities of east central Africa. A case study of how women contribute to saving water in a rural village of Uganda can lay the foundation for understanding the need for more thorough research that documents how women in their roles as cooks and family caregivers think about water as a valuable resource within their community. This example of a case study could also point to the need for scholars to build new theoretical frameworks around the topic [e.g., applying feminist theories of work and family to the issue of water conservation].

Eisenhardt, Kathleen M. “Building Theories from Case Study Research.” Academy of Management Review 14 (October 1989): 532-550; Emmel, Nick. Sampling and Choosing Cases in Qualitative Research: A Realist Approach . Thousand Oaks, CA: SAGE Publications, 2013; Gerring, John. “What Is a Case Study and What Is It Good for?” American Political Science Review 98 (May 2004): 341-354; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Seawright, Jason and John Gerring. "Case Selection Techniques in Case Study Research." Political Research Quarterly 61 (June 2008): 294-308.

Structure and Writing Style

The purpose of a paper in the social sciences designed around a case study is to thoroughly investigate a subject of analysis in order to reveal a new understanding about the research problem and, in so doing, contributing new knowledge to what is already known from previous studies. In applied social sciences disciplines [e.g., education, social work, public administration, etc.], case studies may also be used to reveal best practices, highlight key programs, or investigate interesting aspects of professional work.

In general, the structure of a case study research paper is not all that different from a standard college-level research paper. However, there are subtle differences you should be aware of. Here are the key elements to organizing and writing a case study research paper.

I.  Introduction

As with any research paper, your introduction should serve as a roadmap for your readers to ascertain the scope and purpose of your study . The introduction to a case study research paper, however, should not only describe the research problem and its significance, but you should also succinctly describe why the case is being used and how it relates to addressing the problem. The two elements should be linked. With this in mind, a good introduction answers these four questions:

• What is being studied? Describe the research problem and describe the subject of analysis [the case] you have chosen to address the problem. Explain how they are linked and what elements of the case will help to expand knowledge and understanding about the problem.
• Why is this topic important to investigate? Describe the significance of the research problem and state why a case study design and the subject of analysis that the paper is designed around is appropriate in addressing the problem.
• What did we know about this topic before I did this study? Provide background that helps lead the reader into the more in-depth literature review to follow. If applicable, summarize prior case study research applied to the research problem and why it fails to adequately address the problem. Describe why your case will be useful. If no prior case studies have been used to address the research problem, explain why you have selected this subject of analysis.
• How will this study advance new knowledge or new ways of understanding? Explain why your case study will be suitable in helping to expand knowledge and understanding about the research problem.

Each of these questions should be addressed in no more than a few paragraphs. Exceptions to this can be when you are addressing a complex research problem or subject of analysis that requires more in-depth background information.

II.  Literature Review

The literature review for a case study research paper is generally structured the same as it is for any college-level research paper. The difference, however, is that the literature review is focused on providing background information and  enabling historical interpretation of the subject of analysis in relation to the research problem the case is intended to address . This includes synthesizing studies that help to:

• Place relevant works in the context of their contribution to understanding the case study being investigated . This would involve summarizing studies that have used a similar subject of analysis to investigate the research problem. If there is literature using the same or a very similar case to study, you need to explain why duplicating past research is important [e.g., conditions have changed; prior studies were conducted long ago, etc.].
• Describe the relationship each work has to the others under consideration that informs the reader why this case is applicable . Your literature review should include a description of any works that support using the case to investigate the research problem and the underlying research questions.
• Identify new ways to interpret prior research using the case study . If applicable, review any research that has examined the research problem using a different research design. Explain how your use of a case study design may reveal new knowledge or a new perspective or that can redirect research in an important new direction.
• Resolve conflicts amongst seemingly contradictory previous studies . This refers to synthesizing any literature that points to unresolved issues of concern about the research problem and describing how the subject of analysis that forms the case study can help resolve these existing contradictions.
• Point the way in fulfilling a need for additional research . Your review should examine any literature that lays a foundation for understanding why your case study design and the subject of analysis around which you have designed your study may reveal a new way of approaching the research problem or offer a perspective that points to the need for additional research.
• Expose any gaps that exist in the literature that the case study could help to fill . Summarize any literature that not only shows how your subject of analysis contributes to understanding the research problem, but how your case contributes to a new way of understanding the problem that prior research has failed to do.
• Locate your own research within the context of existing literature [very important!] . Collectively, your literature review should always place your case study within the larger domain of prior research about the problem. The overarching purpose of reviewing pertinent literature in a case study paper is to demonstrate that you have thoroughly identified and synthesized prior studies in relation to explaining the relevance of the case in addressing the research problem.

III.  Method

In this section, you explain why you selected a particular case [i.e., subject of analysis] and the strategy you used to identify and ultimately decide that your case was appropriate in addressing the research problem. The way you describe the methods used varies depending on the type of subject of analysis that constitutes your case study.

If your subject of analysis is an incident or event . In the social and behavioral sciences, the event or incident that represents the case to be studied is usually bounded by time and place, with a clear beginning and end and with an identifiable location or position relative to its surroundings. The subject of analysis can be a rare or critical event or it can focus on a typical or regular event. The purpose of studying a rare event is to illuminate new ways of thinking about the broader research problem or to test a hypothesis. Critical incident case studies must describe the method by which you identified the event and explain the process by which you determined the validity of this case to inform broader perspectives about the research problem or to reveal new findings. However, the event does not have to be a rare or uniquely significant to support new thinking about the research problem or to challenge an existing hypothesis. For example, Walo, Bull, and Breen conducted a case study to identify and evaluate the direct and indirect economic benefits and costs of a local sports event in the City of Lismore, New South Wales, Australia. The purpose of their study was to provide new insights from measuring the impact of a typical local sports event that prior studies could not measure well because they focused on large "mega-events." Whether the event is rare or not, the methods section should include an explanation of the following characteristics of the event: a) when did it take place; b) what were the underlying circumstances leading to the event; and, c) what were the consequences of the event in relation to the research problem.

If your subject of analysis is a person. Explain why you selected this particular individual to be studied and describe what experiences they have had that provide an opportunity to advance new understandings about the research problem. Mention any background about this person which might help the reader understand the significance of their experiences that make them worthy of study. This includes describing the relationships this person has had with other people, institutions, and/or events that support using them as the subject for a case study research paper. It is particularly important to differentiate the person as the subject of analysis from others and to succinctly explain how the person relates to examining the research problem [e.g., why is one politician in a particular local election used to show an increase in voter turnout from any other candidate running in the election]. Note that these issues apply to a specific group of people used as a case study unit of analysis [e.g., a classroom of students].

If your subject of analysis is a place. In general, a case study that investigates a place suggests a subject of analysis that is unique or special in some way and that this uniqueness can be used to build new understanding or knowledge about the research problem. A case study of a place must not only describe its various attributes relevant to the research problem [e.g., physical, social, historical, cultural, economic, political], but you must state the method by which you determined that this place will illuminate new understandings about the research problem. It is also important to articulate why a particular place as the case for study is being used if similar places also exist [i.e., if you are studying patterns of homeless encampments of veterans in open spaces, explain why you are studying Echo Park in Los Angeles rather than Griffith Park?]. If applicable, describe what type of human activity involving this place makes it a good choice to study [e.g., prior research suggests Echo Park has more homeless veterans].

If your subject of analysis is a phenomenon. A phenomenon refers to a fact, occurrence, or circumstance that can be studied or observed but with the cause or explanation to be in question. In this sense, a phenomenon that forms your subject of analysis can encompass anything that can be observed or presumed to exist but is not fully understood. In the social and behavioral sciences, the case usually focuses on human interaction within a complex physical, social, economic, cultural, or political system. For example, the phenomenon could be the observation that many vehicles used by ISIS fighters are small trucks with English language advertisements on them. The research problem could be that ISIS fighters are difficult to combat because they are highly mobile. The research questions could be how and by what means are these vehicles used by ISIS being supplied to the militants and how might supply lines to these vehicles be cut off? How might knowing the suppliers of these trucks reveal larger networks of collaborators and financial support? A case study of a phenomenon most often encompasses an in-depth analysis of a cause and effect that is grounded in an interactive relationship between people and their environment in some way.

NOTE:   The choice of the case or set of cases to study cannot appear random. Evidence that supports the method by which you identified and chose your subject of analysis should clearly support investigation of the research problem and linked to key findings from your literature review. Be sure to cite any studies that helped you determine that the case you chose was appropriate for examining the problem.

IV.  Discussion

The main elements of your discussion section are generally the same as any research paper, but centered around interpreting and drawing conclusions about the key findings from your analysis of the case study. Note that a general social sciences research paper may contain a separate section to report findings. However, in a paper designed around a case study, it is common to combine a description of the results with the discussion about their implications. The objectives of your discussion section should include the following:

Reiterate the Research Problem/State the Major Findings Briefly reiterate the research problem you are investigating and explain why the subject of analysis around which you designed the case study were used. You should then describe the findings revealed from your study of the case using direct, declarative, and succinct proclamation of the study results. Highlight any findings that were unexpected or especially profound.

Explain the Meaning of the Findings and Why They are Important Systematically explain the meaning of your case study findings and why you believe they are important. Begin this part of the section by repeating what you consider to be your most important or surprising finding first, then systematically review each finding. Be sure to thoroughly extrapolate what your analysis of the case can tell the reader about situations or conditions beyond the actual case that was studied while, at the same time, being careful not to misconstrue or conflate a finding that undermines the external validity of your conclusions.

Relate the Findings to Similar Studies No study in the social sciences is so novel or possesses such a restricted focus that it has absolutely no relation to previously published research. The discussion section should relate your case study results to those found in other studies, particularly if questions raised from prior studies served as the motivation for choosing your subject of analysis. This is important because comparing and contrasting the findings of other studies helps support the overall importance of your results and it highlights how and in what ways your case study design and the subject of analysis differs from prior research about the topic.

Consider Alternative Explanations of the Findings Remember that the purpose of social science research is to discover and not to prove. When writing the discussion section, you should carefully consider all possible explanations revealed by the case study results, rather than just those that fit your hypothesis or prior assumptions and biases. Be alert to what the in-depth analysis of the case may reveal about the research problem, including offering a contrarian perspective to what scholars have stated in prior research if that is how the findings can be interpreted from your case.

Acknowledge the Study's Limitations You can state the study's limitations in the conclusion section of your paper but describing the limitations of your subject of analysis in the discussion section provides an opportunity to identify the limitations and explain why they are not significant. This part of the discussion section should also note any unanswered questions or issues your case study could not address. More detailed information about how to document any limitations to your research can be found here .

Suggest Areas for Further Research Although your case study may offer important insights about the research problem, there are likely additional questions related to the problem that remain unanswered or findings that unexpectedly revealed themselves as a result of your in-depth analysis of the case. Be sure that the recommendations for further research are linked to the research problem and that you explain why your recommendations are valid in other contexts and based on the original assumptions of your study.

V.  Conclusion

As with any research paper, you should summarize your conclusion in clear, simple language; emphasize how the findings from your case study differs from or supports prior research and why. Do not simply reiterate the discussion section. Provide a synthesis of key findings presented in the paper to show how these converge to address the research problem. If you haven't already done so in the discussion section, be sure to document the limitations of your case study and any need for further research.

The function of your paper's conclusion is to: 1) reiterate the main argument supported by the findings from your case study; 2) state clearly the context, background, and necessity of pursuing the research problem using a case study design in relation to an issue, controversy, or a gap found from reviewing the literature; and, 3) provide a place to persuasively and succinctly restate the significance of your research problem, given that the reader has now been presented with in-depth information about the topic.

Consider the following points to help ensure your conclusion is appropriate:

• If the argument or purpose of your paper is complex, you may need to summarize these points for your reader.
• If prior to your conclusion, you have not yet explained the significance of your findings or if you are proceeding inductively, use the conclusion of your paper to describe your main points and explain their significance.
• Move from a detailed to a general level of consideration of the case study's findings that returns the topic to the context provided by the introduction or within a new context that emerges from your case study findings.

Note that, depending on the discipline you are writing in or the preferences of your professor, the concluding paragraph may contain your final reflections on the evidence presented as it applies to practice or on the essay's central research problem. However, the nature of being introspective about the subject of analysis you have investigated will depend on whether you are explicitly asked to express your observations in this way.

Problems to Avoid

Overgeneralization One of the goals of a case study is to lay a foundation for understanding broader trends and issues applied to similar circumstances. However, be careful when drawing conclusions from your case study. They must be evidence-based and grounded in the results of the study; otherwise, it is merely speculation. Looking at a prior example, it would be incorrect to state that a factor in improving girls access to education in Azerbaijan and the policy implications this may have for improving access in other Muslim nations is due to girls access to social media if there is no documentary evidence from your case study to indicate this. There may be anecdotal evidence that retention rates were better for girls who were engaged with social media, but this observation would only point to the need for further research and would not be a definitive finding if this was not a part of your original research agenda.

Failure to Document Limitations No case is going to reveal all that needs to be understood about a research problem. Therefore, just as you have to clearly state the limitations of a general research study , you must describe the specific limitations inherent in the subject of analysis. For example, the case of studying how women conceptualize the need for water conservation in a village in Uganda could have limited application in other cultural contexts or in areas where fresh water from rivers or lakes is plentiful and, therefore, conservation is understood more in terms of managing access rather than preserving access to a scarce resource.

Failure to Extrapolate All Possible Implications Just as you don't want to over-generalize from your case study findings, you also have to be thorough in the consideration of all possible outcomes or recommendations derived from your findings. If you do not, your reader may question the validity of your analysis, particularly if you failed to document an obvious outcome from your case study research. For example, in the case of studying the accident at the railroad crossing to evaluate where and what types of warning signals should be located, you failed to take into consideration speed limit signage as well as warning signals. When designing your case study, be sure you have thoroughly addressed all aspects of the problem and do not leave gaps in your analysis that leave the reader questioning the results.

Case Studies. Writing@CSU. Colorado State University; Gerring, John. Case Study Research: Principles and Practices . New York: Cambridge University Press, 2007; Merriam, Sharan B. Qualitative Research and Case Study Applications in Education . Rev. ed. San Francisco, CA: Jossey-Bass, 1998; Miller, Lisa L. “The Use of Case Studies in Law and Social Science Research.” Annual Review of Law and Social Science 14 (2018): TBD; Mills, Albert J., Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Putney, LeAnn Grogan. "Case Study." In Encyclopedia of Research Design , Neil J. Salkind, editor. (Thousand Oaks, CA: SAGE Publications, 2010), pp. 116-120; Simons, Helen. Case Study Research in Practice . London: SAGE Publications, 2009;  Kratochwill,  Thomas R. and Joel R. Levin, editors. Single-Case Research Design and Analysis: New Development for Psychology and Education .  Hilldsale, NJ: Lawrence Erlbaum Associates, 1992; Swanborn, Peter G. Case Study Research: What, Why and How? London : SAGE, 2010; Yin, Robert K. Case Study Research: Design and Methods . 6th edition. Los Angeles, CA, SAGE Publications, 2014; Walo, Maree, Adrian Bull, and Helen Breen. “Achieving Economic Benefits at Local Events: A Case Study of a Local Sports Event.” Festival Management and Event Tourism 4 (1996): 95-106.

Writing Tip

At Least Five Misconceptions about Case Study Research

Social science case studies are often perceived as limited in their ability to create new knowledge because they are not randomly selected and findings cannot be generalized to larger populations. Flyvbjerg examines five misunderstandings about case study research and systematically "corrects" each one. To quote, these are:

Misunderstanding 1 :  General, theoretical [context-independent] knowledge is more valuable than concrete, practical [context-dependent] knowledge. Misunderstanding 2 :  One cannot generalize on the basis of an individual case; therefore, the case study cannot contribute to scientific development. Misunderstanding 3 :  The case study is most useful for generating hypotheses; that is, in the first stage of a total research process, whereas other methods are more suitable for hypotheses testing and theory building. Misunderstanding 4 :  The case study contains a bias toward verification, that is, a tendency to confirm the researcher’s preconceived notions. Misunderstanding 5 :  It is often difficult to summarize and develop general propositions and theories on the basis of specific case studies [p. 221].

While writing your paper, think introspectively about how you addressed these misconceptions because to do so can help you strengthen the validity and reliability of your research by clarifying issues of case selection, the testing and challenging of existing assumptions, the interpretation of key findings, and the summation of case outcomes. Think of a case study research paper as a complete, in-depth narrative about the specific properties and key characteristics of your subject of analysis applied to the research problem.

Flyvbjerg, Bent. “Five Misunderstandings About Case-Study Research.” Qualitative Inquiry 12 (April 2006): 219-245.

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Critical case sampling

A critical case is one that permits analytic generalisation, as, if a theory can work in the conditions of the critical case, it's likely to be able to work anywhere.

Characteristics of particular cases may make them critical – level of education of the population, level of pollution of the environment, level of resistance to government intervention of a community. The purpose of the evaluation is to investigate the success of the program in this particular critical case. Commissioners of the evaluation may be interested in the results of the evaluation for logical generalisation to other sites.

Polar regions and small island states are identified by scientists as critical cases in investigating the phenomenon of climate change. These sites are monitored closely for environmental changes. By investigating these sites in depth, scientists hope to develop knowledge that can be applied to other sites.

Suppose national policymakers want to get local communities involved in making decisions about how their local program will be run, but they aren't sure that the communities will understand the complex regulations governing their involvement. The first critical case is to evaluate the regulations in a community of well-educated citizens. If they can't understand the regulations, then less-educated folks are sure to find the regulations incomprehensible. Or, conversely, one might consider the critical case to be a community consisting of people with quite low levels of education: 'If they can understand the regulations, anyone can.' (Patton 2014: 276)

Focuses on identifying ‘outliers’ – those with exceptional outcomes - and understanding their experience as compared to others.

Analytical generalisation involves making projections about the likely transferability of findings from an evaluation, based on a theoretical analysis of the factors producing outcomes and the effect of context.

Patton, M. Q. (2014).  Qualitative Research & Evaluation Methods: Integrative Theory and Practice ​. SAGE Publications.

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• Published: 17 May 2024

Case volume and specialization in critically ill emergency patients: a nationwide cohort study in Japanese ICUs

• Jun Fujinaga   ORCID: orcid.org/0000-0001-6222-7292 1 ,
• Takanao Otake 1 ,
• Takehide Umeda 1 , 2 &
• Toshio Fukuoka 1  

Journal of Intensive Care volume  12 , Article number:  20 ( 2024 ) Cite this article

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Previous studies have explored the association between the number of cases and patient outcomes for critical illnesses such as sepsis and trauma, as well as various surgeries, with the expectation that a higher number of cases would have a more favorable effect on patient outcomes. The aim of this study was to elucidate the association among intensive care unit (ICU) case volume, specialization, and patient outcomes in critically ill emergency patients and to determine how ICU case volumes and specializations impact the outcomes of these patients in Japanese ICUs.

Utilizing data from the Japanese Intensive Care PAtient Database (JIPAD) from April 2015 to March 2021, this retrospective cohort study was conducted in 80 ICUs across Japan and included 72,214 emergency patients aged ≥ 16 years. The primary outcome measure was in-hospital mortality, and the secondary outcomes encompassed ICU mortality, 28-day mortality, ventilator-free days, and the lengths of ICU and hospital stays. Bayesian hierarchical generalized linear mixed models were used to adjust for patient- and ICU-level variables.

This study revealed a significant association between a higher ICU case volume and decreased in-hospital mortality. In particular, ICUs with a higher percentage (> 75%) of emergency patients showed more pronounced effects, with the odds ratios for in-hospital mortality in the higher case volume quartiles (Q2, Q3, and Q4) being 0.92 (95% credible interval [CI]: 0.88–0.96), 0.70 (95% CI: 0.67–0.73), and 0.78 (95% CI: 0.73–0.83), respectively, compared with the lowest quartile (Q1). Similar trends were observed for various secondary outcomes.

Conclusions

Higher ICU case volumes were significantly associated with lower in-hospital mortality rates in Japanese ICUs predominantly treating critically ill emergency patients. These findings emphasize the importance of ICU specialization and highlight the potential benefits of centralized care for critically ill emergency patients. These findings are potential insights for improving health care policy in Japan and may be valuable in emergency care settings in other countries with similar healthcare systems, after careful consideration of contextual differences.

Previous studies have explored the association between the number of cases and patient outcomes for critical illnesses such as sepsis and trauma and various surgeries, with the expectation that a higher number of cases would have a more favorable effect on patient outcomes [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Therefore, a positive relationship between case volume and outcome in a broader emergency patient population is expected. However, no such studies have been conducted.

In Japan’s emergency medical care system, critically ill emergency patients are admitted to intensive care units (ICUs) dedicated to emergency patients or to ICUs that also admit critically ill patients whose condition deteriorated while being treated on the general ward and patients after major surgery. These two types of ICUs in Japan exist in roughly equal numbers [ 9 ]. In addition to the different nature of each type, the number and proportion of emergency patients admitted to ICUs is expected to vary widely, depending on the individual hospital and the nature of the local healthcare system. Despite the potentially important role these differences could have on patient outcome, no comprehensive study has examined the effect of ICU specialization and case volume on patient outcomes within the Japanese emergency medical care framework. Therefore, the aim of this study was to examine the association between critically ill emergency patient case volumes, specialization, and outcomes by using a nationwide database to provide valuable insights into the optimization of emergency care.

Study design and data

This retrospective cohort study used data from the Japanese Intensive Care PAtient Database (JIPAD), a national registry established by the Japanese Society of Intensive Care Medicine (JSICM) to create a high-quality ICU database. The details of this registry have been previously described [ 10 ]. The JIPAD was initiated in 2014, and data have been available since fiscal year (FY) 2015.

Patients aged ≥ 16 years who were registered in the JIPAD between April 1, 2015 and March 31, 2021 included emergency patients admitted directly from the emergency department (ED), emergency patients admitted after surgery, emergency patients transferred from other hospitals, and patients transferred from non-ICU wards or care units within 2 days of emergency admission.

Patients were excluded who were transferred from non-ICU care units or wards after 2 days of emergency admission, had planned admissions, and were admitted to the ICU only for procedures. Facilities with missing information on the ICU staff (e.g., dedicated intensivists and dedicated ICU nurses) and on patients admitted to these facilities, and patients with missing Japan Risk of Death (JROD) scores [ 11 ] were excluded because they lacked essential information. Facilities having < 10 eligible patients per year and patients admitted to these facilities were excluded to address heterogeneity in patient care. The JROD score is a prognostic score calibrated for Japanese ICU patients, based on the Acute Physiology and Chronic Health Evaluation III-j scoring system [ 11 , 12 ].

Ethics statement

This study was approved by the Institutional Ethics Committee of Kurashiki Central Hospital (approval number: 4266; approval date: November 5, 2023). The committee confirmed that this study adheres to national ethical guidelines and the Declaration of Helsinki. All patients were de-identified, and the need for informed consent was waived.

Patient-level variables collected at admission included the JROD score, Sequential Organ Failure Assessment score, age, sex, underlying disease, body mass index (BMI), emergency surgery, cardiac resuscitation before admission, route of admission (i.e., ED, operating room, transfer from another hospital, non-ICU care unit, or ward), and disease group diagnosed at admission. We collected data on various invasive procedures performed in the ICU such as extracorporeal membrane oxygenation (venovenous or venoarterial), invasive mechanical ventilation, and the administration of continuous renal replacement therapy. Additionally, the fiscal years of admission and length of hospitalization were recorded. Facility-level data such as the type of hospital (university hospital or nonuniversity hospital), the proportion of emergency admissions, the number of intensivists and nurses, and the quantity of ICU and hospital beds were also collected.

Study outcomes

The primary outcome assessed was in-hospital mortality. Secondary outcomes included ICU mortality, 28-day mortality, ventilator-free days (VFDs) 28 days after admission, total length of ICU stay, and length of hospital stay. We defined VFDs as the number of days alive and free of invasive mechanical ventilation during the first 28 days after admission (i.e., 0 days if the patient died within 28 days or received invasive mechanical ventilation for > 28 days) [ 13 ].

Statistical analysis

We divided each ICU by the quartile of the average number of eligible patients admitted per year and described the patient and facility characteristics for each quartile. Categorical data are presented as the number and percentage, and continuous variables are presented as the median and interquartile range (IQR). We calculated the risk-standardized mortality ratio (RSMR) [ 14 ] for each ICU by using the number of deaths in each ICU and the JROD score for each patient. We compared each ICU by using a funnel plot of the RSMR.

To account for our two-level hierarchy data structure, we used Bayesian hierarchical generalized linear mixed models with ICU-specific random effects, while adjusting for patient- and ICU-level variables as the fixed effects, and allowing for heterogeneity between ICUs. A random intercept was calculated for each ICU. We estimated an ‘‘empty’’ model (Model 1), which only included each ICU as a random intercept and allowed the detection of in-hospital mortality in various ICUs. The ICU-level random effect of the intercept was assumed to be normally distributed, with a mean value of zero. Thereafter, we estimated the full model (Model 2) to assess the association between case volume and in-hospital mortality by using patient- and ICU-level variables. Logistic regression was applied to in-hospital mortality, ICU mortality, and 28-day mortality. Linear regression models were applied to VFDs at 28 days, total length of ICU stay, and length of hospital stay. Patient-level variables were adjusted for age, sex, JROD score, BMI, cardiac resuscitation before admission, emergency surgery, admission diagnosis, and hospitalization period (FY 2015–2019 or FY 2020–2021). We classified the patients’ BMI into categories appropriate for Asian populations [ 15 ]. We adjusted for the type of hospital (university hospital or nonuniversity hospital), number of beds, number of intensivists per ICU bed, number of nurses per ICU bed, and percentage of emergency patients among all admitted patients. The number of beds in each hospital was classified into quartiles. The proportion of emergency patients to all admitted patients was divided into four quadrants, separated by 25%. Each quartile group was stratified, based on the percentage of emergency patients among all patients admitted to each ICU (Model 3), to assess the effects of case volume and specialization on critical emergency patients. We defined the 75% threshold as the “emergency patient-dominant group.” The threshold of 50% or 90% was used for the sensitivity analysis. Markov chain Monte Carlo (MCMC) methods were used to calculate the odds ratios (ORs) or regression coefficients and their corresponding 95% credible intervals (CIs). In the MCMC process, the first 2500 simulations were discarded as the burn-in and the remaining 10,000 simulations were obtained. Normal priors were used for the fixed effects, and noninformative uniform priors were used for the variance of each ICU in the mixed-effects model. The median ORs (MORs) were computed for ICU-level variance [ 16 , 17 ]. All analyses were performed using the Stata version 16.1 software (Stata, College Station, TX, USA).

Patients and ICU characteristics

We identified 248,908 ICU admission records from 89 ICUs. After applying the exclusion criteria, a total of 80 centers and 72,214 participants were included in the analysis (Fig.  1 ). Table 1 and Supplementary Table 1 show the patients’ characteristics for each quartile of the number of eligible patients in each ICU. The characteristics of the ICUs for each quartile of the number of patients are described in Table  2 . The annual number of eligible admissions was 352 (215.8–469.5) with 152 (118.6–192.3) in the first quartile (Q1), 294 (266.7–318.3) in the second quartile (Q2), 396.6 (391–459.8) in the third quartile (Q3), and 682.5 (541.8–699.3) for the fourth quartile (Q4). A total of 10,704 (14.8%) patients died during hospitalization with a VFD of 23 days.

Study flow diagram. The included patients are 16 years or older. They were enrolled in the JIPAD between April 2015 and March 2021 and were admitted immediately to the ICU or the next day after hospital admission. The exclusion criteria applied to facilities missing ICU staff data, patients lacking JROD scores, and facilities with fewer than 10 qualifying patients annually among their patients. JIPAD Japanese Intensive Care PAtient Database, ICU intensive care unit, JROD Japan Risk of Death

Risk-standardized mortality ratio

The RSMR for each ICU are shown in Fig.  2 . The variation in the RSMR was higher in ICUs with fewer emergency admissions, especially those with less than 200 admissions.

Funnel plots showing risk-standardized mortality rates among ICUs. The overall distribution is presented using the mean mortality ratio (solid line) and the control limits of 95% (dashed line) and 99.8% (dotted line). Each circle represents a single ICU

• In-hospital mortality

The ORs for the in-hospital mortality rates are shown in Table  3 and Supplementary Table 2. In Model 2, higher ICU volumes were associated with decreased in-hospital mortality. We evaluated the association between case volume and in-hospital mortality, adjusted for patient-level and ICU-level variables, and found that the ORs for Q3 and Q4 were 0.92 (95% CI: 0.88–0.95) and 0.93 (95% CI: 0.88–0.99), respectively, indicating decreased in-hospital mortality, compared with Q1. In Model 1, the MOR is 1.40 (95% CI: 1.32–1.49), indicating a significant variation in in-hospital mortality at the ICU level. In Model 2, adjusted for patient-level and ICU-level variables, we found a smaller MOR of 1.07 (95% CI: 1.02–1.12).

Secondary outcomes

Results for the secondary outcomes are shown in Supplementary Table 3. Q4 had ORs of 1.32 (95% CI: 1.24–1.41) and 1.12 (95% CI: 1.09–1.15) for ICU deaths and 28-day deaths, respectively. These values remained large after adjusting for patient-level and ICU-level variables in Model 2, but were inconsistent with the results for in-hospital mortality. We found that the case volume did not affect VFDs, ICU length of stay, or the reduced hospital length of stay in Q3 and Q4.

Stratified analyses

In Model 3, the quartiles were further stratified and examined, based on the percentage of emergency patients (i.e., > 75%). In Q1, no ICUs were included in the “emergency patient-dominant group” stratum. The findings of the study suggests that case volume had a larger effect on ICUs with an “emergency patient-dominant group” strata, as indicated by the lack of overlap in their respective 95% CI ranges (Fig.  3 ). The ORs for Q2, Q3, and Q4 in this stratum were 0.92 (95% CI: 0.88–0.96), 0.70 (95% CI: 0.67–0.73), and 0.78 (95% CI: 0.73–0.83), respectively. In-hospital mortality rates were lower in Q2, Q3, and Q4 than in Q1, even in ICUs with emergency patient ratios of < 75%. Sensitivity analyses were similar when the thresholds were set at 90% and 50% (Supplementary Table 4).

In-hospital mortality, stratified by the number of ICU admissions and percentage of emergency patients. Odds ratios were calculated using a multilevel logistic regression model, thereby allowing for a random effect (i.e., random intercept) model for each ICU. We adjusted ICU-level and patient-level variables, as follows: age, sex, BMI (< 18.5, 18.5–23, 23–27.5, and ≥ 27.5), JROD score, diagnosis at admission and after cardiac resuscitation, emergency surgery, hospitalization period (from FY 2015 through FY 2019 and from FY 2020 through FY 2021), number of nurses per ICU beds, number of intensivists per ICU beds, quartile of hospital beds, and type of hospital (university hospital or nonuniversity hospital). ICU intensive care unit, JROD Japan Risk of Death, BMI body mass index, FY fiscal year, Ref. reference

The stratified analysis of secondary outcomes is shown in Supplementary Table 5. For the “emergency patient-dominant group,” Q4 showed a reduction in ICU mortality with an OR of 0.77 (95% CI; 0.73–0.82), indicating heterogeneity in the association between case volume and outcome, depending on the frequency of emergency patients.

This study assessed the effects of case volume and specialization on the outcomes of critically ill emergency patients by using a comprehensive ICU patient database. The results revealed that higher ICU case volumes were associated with lower in-hospital mortality rates, particularly in ICUs with higher proportions of emergency patients.

This association is consistent with the findings of previous studies [ 2 , 3 , 7 , 8 , 18 ] conducted on other certain emergencies, supporting the learning curve hypothesis [ 18 ]. Another possible mechanism is that the ICUs in the lowest quartile (Q1) had fewer ICU beds relative to total hospital beds (Table  2 ), suggesting limited resources. Although these ICUs may treat more severely ill patients, the impact of bed count is minimal because adjustments were made for illness severity and staff number. Our analysis also revealed a nonlinear association between case volume and patient outcomes. This U-shaped association was more evident for ICU mortality and 28-day mortality, suggesting that a similar mechanism may exist as that described in a previous studies [ 19 , 20 ] in which an excess case volume was negatively associated with mortality. However, as shown in Supplementary Table 5, we observed differences in short-term mortality rates and hospital mortality rates in Q4, depending on the proportion of emergency patients. This indicates that the effect of case volume on short-term mortality is heterogeneous across the proportion of emergency patients in the ICU.

Furthermore, the stratified analysis by proportion of emergency patients showed a more obvious reduction in in-hospital mortality in ICUs with a predominantly emergency patient population, which may be because of the positive impact of ICU specialization. These ICUs may be well resourced and experienced in the treatment of emergency conditions, which may lead to better patient outcomes.

In this study, the MOR for in-hospital mortality was low (MOR 1.07; 95% CI: 1.02–1.12), indicating little variation in in-hospital mortality among ICUs. However, the MOR for short-term mortality, especially ICU mortality, was significantly higher (MOR 1.36; 95% CI: 1.27–1.46), suggesting a notable disparity in short-term outcomes, which were potentially influenced by ICU-level and patient-level variables. The MOR is defined as the median value of the OR between the highest and lowest risk clusters; if two clusters are chosen at random, the MOR indicates the increased risk (in median) of moving to another higher-risk cluster [ 16 ].

The MOR for ICU mortality increased substantially, suggesting a significant variation in short-term mortality risk across ICUs, which cannot be fully explained by ICU- or patient-level variables. These MOR results may have been derived from differences between the ICUs that were not captured in this dataset. Factors that may have created variations include ICU practices and protocols (e.g., differences in treatment protocols, staffing, and available resources), admission criteria (e.g., variation in patient admission criteria that may affect the risk profile of ICU patients), discharge criteria (affecting the length of ICU stay), facility characteristics (e.g., lack of high-dependency care units, which may affect admission and discharge criteria), and regional differences in the provision and use of critical care beds [ 21 ]. These findings indicate that further investigation of the factors affecting patient outcomes in the ICUs is required.

The RSMR for in-hospital mortality for each ICU (Fig.  2 ) could be appropriately compared with that of the entire population by using a funnel plot [ 14 ], showing the variation in the RSMR for ICUs with fewer emergency admissions. This finding suggests disparities in resources, quality of care, or patient population characteristics. This disparity was supported by the multilevel analysis (Model 2), which showed increased in-hospital mortality in ICUs with fewer than 200 emergency admissions per year (Q1), after adjusting for patient characteristics and ICU resources. Higher-case-volume ICUs may have lower RSMRs, possibly because of factors such as experienced staff, effective protocols, and resource availability.

The RSMR is a crucial indicator of quality of care but must be interpreted in conjunction with other indicators, such as the length of stay and readmission rates, for a comprehensive view of ICU performance. When calculating the RSMR, the method of risk adjustment must be considered to avoid misleading results—particularly if certain high-risk patient populations are inadequately accounted for. We improved the reliability of our results by using the JROD score [ 11 ], a newly developed index for intensive care patients in Japan. However, missing values or reporting bias when calculating the RSMR could affect the accuracy and reliability of the results.

One strength of this study was the use of the JIPAD, which registers various ICUs nationwide and regularly undertakes efforts to maintain data accuracy [ 22 ]. It is the most reliable database for ICUs in Japan in terms of size, reliability, and precision. Therefore, we believe that the participants and facilities in this study represent a highly representative population of emergency patients requiring intensive care in Japan.

This study has some limitations. Each facility in the JIPAD is anonymized; therefore, we classified the participating facilities, based on the ratio of emergencies to admitted patients. Second, a possibility of selection bias existed because five of nine centers were excluded because they had a small number of potentially eligible patients, they treated primarily pediatric patients, and were highly heterogeneous, whereas the other four centers lacked information on the number of intensivists and nurses. Although information on the number of intensivists and nurses was lacking, the small number of excluded patients had little impact on the results. Third, participation in the JIPAD was voluntary; therefore, the participating ICUs may have been more proactive in improving the quality of care. ICUs with larger case volumes or a higher proportion of emergency patients are more likely to participate in the JIPAD, which may cause further selection bias. Nevertheless, analyzing a homogeneous population increases the validity of comparisons and the reliability of statistical analysis. Furthermore, caution should be exercised when generalizing the results because these ICUs may not be fully representative of all ICUs in Japan. Fourth, we were unable to assess the proficiency or years of experience of the ICU staff. In Japan, intensivists typically have a background in emergency medicine or anesthesia [ 23 ]. We also could not assess differences in the background of intensivists. These differences could have influenced the patient outcomes, and therefore require further investigation into the effect of the expertise and training of ICU staff on patient outcomes. A fifth limitation is differences in healthcare systems. Extrapolating the results of this study to other countries may be limited by differences in healthcare systems, especially in ICU settings. However, extrapolation to other countries may be possible. Even after considering the effects of these differences, the results of this study may be relevant beyond the Japanese healthcare system. For instance, a comparable mechanism may be responsible for favorable patient outcomes in the emergency department intensive care unit (ED-ICU) system in the United States [ 24 ] or in ICUs where emergency physicians led operations in South Korea [ 25 ]. Specifically, this improvement in outcomes can be attributed to the shortened time to ICU admission for emergency patients, effective coordination between the ED and ICU, reduced length of stay in the ED, and a comprehensive understanding of the patients’ condition. Nevertheless, direct comparisons among different healthcare systems should be made with caution. Finally, the utilization of critical care and emergency medical systems in Japan was affected by the COVID-19 pandemic since April 2020 (FY 2020 and beyond) [ 26 , 27 , 28 ], which may have an impact on patient outcomes. Thus, we categorized data entry into two periods: FY 2015–2019 and FY 2020–2021. Future research could potentially focus on exploring the impact of different ICU characteristics and healthcare reimbursement classifications on critically ill patient outcomes. This research could involve examining factors, such as ICU size, patients’ demographics, and financial incentives within the reimbursement system, to better understand how these factors may influence care quality.

Higher case volumes and specialization of critically ill emergency patients are associated with a lower risk of in-hospital mortality. Based on these results, we recommend that critically ill emergency patients be centralized and admitted to specialized ICUs for emergency patients to optimize the emergency care system. Meanwhile, significant variability existed among ICUs in short-term mortality. Future studies focusing on regional differences and staff specialization are needed to determine the causes contributing to this variation.

Availability of data and materials

The author’s agreement with the JIPAD does not allow publishing the data used for this manuscript or sharing it with others. The JIPAD Working Group would cooperate in case any fraud or forgery is suspected in manuscripts in which JIPAD data are used.

Abbreviations

Body mass index

Credible interval

Emergency department

Fiscal year

Intensive care unit

Interquartile range

Japan Risk of Death

Japanese Intensive Care PAtient Database

Japanese Society of Intensive Care Medicine

Median odds ratio

Ventilator-free day

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Acknowledgements

We would like to thank the JIPAD Working Group in the Japanese Society of Intensive Care Medicine (Tokyo, Japan) for their help with this study.

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Jun Fujinaga, Takanao Otake, Takehide Umeda & Toshio Fukuoka

Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Kita-Ku, Okayama, 700-8558, Japan

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JF conceived the fundamental idea and the study design, analyzed the data, and drafted the manuscript. TO and TU provided advice on study design, data analysis and interpretation, and critically revised the manuscript. TF supervised the conduct of the study and data collection and critically revised the manuscript. JF takes responsibility for the paper as a whole. All authors have read and approved the final manuscript.

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This study was approved by the Institutional Ethics Committee of Kurashiki Central Hospital (Kurashiki City, Japan; approval number: 4266; approval date: November 5, 2023). The committee confirmed that this study adheres to national ethical guidelines and the Declaration of Helsinki. All patients were de-identified, and the need for informed consent was waived.

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The authors declare no conflicts of interest associated with this manuscript. TF is supported by the Japan Agency for Medical Research and Development (AMED) (Grant number: 22lk0201085h0005). The funding sources had no role in the study design; in the collection, analysis and interpretation of data; in the writing of the manuscript; and in the decision to submit the manuscript for publication.

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Fujinaga, J., Otake, T., Umeda, T. et al. Case volume and specialization in critically ill emergency patients: a nationwide cohort study in Japanese ICUs. j intensive care 12 , 20 (2024). https://doi.org/10.1186/s40560-024-00733-3

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The reliability of the College of Intensive Care Medicine of Australia and New Zealand “Hot Case” examination

• Kenneth R. Hoffman 1 , 2 ,
• David Swanson 3 ,
• Stuart Lane 4 ,
• Chris Nickson 1 , 2 ,
• Paul Brand 5 &
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High stakes examinations used to credential trainees for independent specialist practice should be evaluated periodically to ensure defensible decisions are made. This study aims to quantify the College of Intensive Care Medicine of Australia and New Zealand (CICM) Hot Case reliability coefficient and evaluate contributions to variance from candidates, cases and examiners.

This retrospective, de-identified analysis of CICM examination data used descriptive statistics and generalisability theory to evaluate the reliability of the Hot Case examination component. Decision studies were used to project generalisability coefficients for alternate examination designs.

Examination results from 2019 to 2022 included 592 Hot Cases, totalling 1184 individual examiner scores. The mean examiner Hot Case score was 5.17 (standard deviation 1.65). The correlation between candidates’ two Hot Case scores was low (0.30). The overall reliability coefficient for the Hot Case component consisting of two cases observed by two separate pairs of examiners was 0.42. Sources of variance included candidate proficiency (25%), case difficulty and case specificity (63.4%), examiner stringency (3.5%) and other error (8.2%). To achieve a reliability coefficient of > 0.8 a candidate would need to perform 11 Hot Cases observed by two examiners.

The reliability coefficient for the Hot Case component of the CICM second part examination is below the generally accepted value for a high stakes examination. Modifications to case selection and introduction of a clear scoring rubric to mitigate the effects of variation in case difficulty may be helpful. Increasing the number of cases and overall assessment time appears to be the best way to increase the overall reliability. Further research is required to assess the combined reliability of the Hot Case and viva components.

Peer Review reports

Credentialling medical specialists requires defined performance standards [ 1 , 2 ] and traditionally relies upon high stakes examinations to assess trainees against those standards [ 3 , 4 , 5 ]. These examinations substitute for controlling quality of care by attempting to control progression through training programs for the safety of both patients and society. Specialist colleges are also expected to provide transparent and fair assessment processes, to ensure defensible decisions are made regarding trainee progression and specialist credentialling [ 6 ].

The College of Intensive Care Medicine of Australia and New Zealand (CICM) second part examination was introduced in 1979 and has undergone many revisions [ 3 ]. It has two components: a written examination and, if completed successfully, an oral examination. The oral examination includes an eight-station viva assessment and two clinical “Hot Case” assessments. This Hot Case component targets the highest level of assessment on Miller’s Pyramid [ 7 ], ‘Does’, requiring candidates to be assessed in the workplace performing real-world tasks. Of the candidates who have passed the written examination successfully, only 35% pass both Hot Cases [ 8 ]. It is therefore important to evaluate both the validity of inferences from this examination component and the reliability or reproducibility of the results [ 9 ].

Reliability describes the degree to which variation in scores reflects true variability in candidates’ proficiency, rather than measurement error. This is dependent on the task, examiner stringency and assessment context [ 10 ]. Reliability can be quantified using the reliability coefficient, with 0 representing a completely unreliable assessment and 1 representing a completely reliable assessment. The minimum standard generally considered acceptable for high stakes medical examinations is a reliability coefficient greater than 0.8 [ 11 , 12 , 13 , 14 ].

Generalisability theory (G-theory) provides the statistical basis for combining multiple sources of variance into a single analysis [ 15 ]. This enables the calculation of an overall reliability coefficient and calculation of the contribution from candidates, cases and examiners to examination reliability. G-theory also provides the basis for conducting decision studies (D-studies) that statistically project reliability based on alternate assessment designs.

To date, no information on the reliability of the CICM second part examination has been published. Given the implications of incorrect credentialling decisions for trainees, patients and society, the Hot Case reliability coefficient should be quantified.

Examination format

The second part examination prior to COVID-19 was held twice yearly with candidates invited to the oral component in a single Australian city. Trainees complete two Hot Cases within metropolitan intensive care units (ICU) with 20 min allocated for each: 10 min to examine an ICU patient, followed by 10 min with paired examiners to present their findings and answer questions regarding investigations and clinical management.

Format changes occurred during the COVID-19 pandemic. The first oral examination was cancelled in 2020, with trainees deferring to the second sitting. Additionally, travel restrictions meant candidates sat the Hot Case component in their home city with local examiners from the second sitting in 2020 to the second sitting in 2021. From 2022 onwards, the oral examination has been held in Sydney, Melbourne, or both.

Hot Cases are marked out of 10 by two CICM examiners using a rating scale that scores candidates based on how comfortable examiners would be supervising them. An acceptable pass standard (5/10) indicates an examiner is comfortable to leave the candidate in charge of the ICU with minimal supervision. There is no specific scoring rubric, although examiner pairs cooperatively determine clinical signs that should be identified, nominate investigations and imaging to show a candidate, and specify discussion questions. Expected levels of knowledge, interpretation and clinical management are defined prospectively. An automatic fail for the entire oral examination is triggered if candidates fail both Hot Cases and obtain a Hot Case component mark < 40% of the possible marks.

Examiner calibration

Examiners undergo calibration training prior to the examination. They independently score the candidate, then discuss their individual scores and rationale. Examiners can then amend their score before recording final scores in the examination database. Each Hot Case is marked by separate pairs of examiners, to prevent bias from a candidates first case performance influencing their second case score. Following the examination, results are presented to the whole examiner cohort for further discussion and explanation.

Data collection

The CICM provided access to their examination database from the second sitting of 2012 (2012-2) through to the first sitting of 2022 (2022-1). For each de-identified candidate, the written mark, overall Hot Case mark, viva mark, and overall examination mark were obtained. The Hot Case specific data included the cases used, examiners present and individual examiner marks, with a total of four scores per candidate (two examiner scores for each Hot Case).

Analysis was restricted to 2019-1 to 2022-1 due to data recording inconsistency providing insufficient data for G-theory analysis. Additionally, changes occurred from 2019-1 with the introduction of the Angoff standard setting method [ 16 , 17 ] for the written examination. This altered final score calculation with the written examination functioning as a barrier examination, although the written score no longer contributes to the final examination score. Candidates were included if they sat the oral examination for the first time in 2019 or later and, if they failed, subsequent attempts were recorded.

Statistical analysis

Statistical analysis used Microsoft Excel and SPSS. Continuous examination scores were summarised using mean and standard deviation. Categorical variables were reported as counts and percentages. Frequency distributions (histograms) were used to graph overall examination component results. A p-value of < 0.05 indicated statistical significance. Comparisons of examiner marks and relationships between examination components were analysed with Pearson’s correlation coefficient and visually represented with scatterplots.

G-theory analysis was used to calculate an overall reliability coefficient for the Hot Case examination, and the factors contributing to variance. As examiners observed multiple candidates and candidates performed multiple Hot Cases, the design was partially crossed. However, as the case identification numbers used in the examination were recorded variably, the initial design was modified to treat cases as nested within candidates for the analysis. The variance factors being analysed included candidate proficiency, examiner stringency, case to case performance variability (case specificity) and other unspecified measurement error. These were reported with variance components, square roots of variance components and percentage of total variance. G-theory was used to conduct D-studies exploring the impact of alternate assessment designs on overall generalisability coefficients and associated standard errors of measurement. The D-study calculated the generalisability coefficient based on the equation listed in Fig.  1 .

Generalisability coefficient equation

Overall, there were 889 candidate oral examination attempts from 2012-2 to 2022-1. After exclusion of candidate oral examination attempts prior to the 2019-1 sitting, exclusion of candidates with first attempts prior to 2019-1 and exclusion of one candidate with missing Hot Case scores, there were 296 candidate oral examination attempts analysed. This included 166 first attempts, 100 s and 30 third attempts. This resulted in 592 Hot Case results and 1184 individual examiner Hot Case scores. The recruitment, exclusion and analysis of the sample are presented in Fig.  2 .

CONSORT style diagram demonstrating the sample size from data request through to the sample available for analysis

The mean and standard deviation of individual examiner Hot Case scores from all examiners was 5.17 and 1.65 respectively. Of the 1184 Hot Case individual examiner scores, 645 (54.5%) achieved a score 5 or greater, and 539 (45.5%) scored less than 5. The distribution of individual examiner Hot Case scores is presented in Fig.  3 . First attempt candidates scored higher than those repeating (5.25 (SD1.63) vs. 4.89 (SD1.66) p  = < 0.01).

Histogram showing individual examiner Hot Case scores for all attempts

Scores on each Hot Case are calculated as the mean of the two individual examiner Hot Case scores. Overall, 312 of 592 Hot Cases were passed (52.7%). The correlation coefficient between candidates first and second Hot Cases was low at 0.30 (Fig.  4 ).

The correlation between each candidate’s first and second Hot Case scores. A jitter function was applied to spread overlying points

The correlation coefficient between examiners observing the same case (inter-rater agreement) was high at 0.91 (Fig.  5 ).

The summary of sources of variance for individual examiner Hot Case scores is presented in Table  1 .

Comparison between Hot Case scores from the first and second examiners. A jitter function was applied to spread overlying points

The overall generalisability coefficient of the Hot Case component including two separate cases observed by two examiners each was 0.42.

The results for the D-studies are presented in Table  2 . To achieve a generalisability coefficient of 0.8 or greater, 11 Hot Cases with two examiners would be needed. A graph comparing the generalisability coefficients for one and two examiners is presented in Fig.  6 .

Generalisability coefficients with a variable number of cases comparing examination designs with one and two examiners observing each case

The current examination format with two Hot Cases observed by two examiners has a reliability coefficient of 0.42. To achieve the widely accepted standard for high stakes examinations of a reliability coefficient of > 0.8 requires each candidate to sit 11 Hot Cases with two examiners.

These results are similar to The Royal Australasian College of Physicians (RACP) 60-minute long case examination observed by two examiners which has a reliability coefficient of 0.38 [ 18 ]. When the assessment time is lengthened with two long cases and four short cases, the RACP achieved a reliability coefficient of 0.71. The RACP continues to use long case examinations, as they are valued by examiners and trainees as an authentic measure of competence with an educational impact from examination preparation [ 18 ]. Educational impact is commonly cited as a reason to retain clinical examinations [ 4 , 19 , 20 ].

G-theory analysis demonstrates that examiners appear well calibrated, as examiner variance was responsible for only 3.5% of overall variance in Hot Case scores. Therefore, adding additional examiners would not substantially improve reliability. However, this conclusion may be affected by the extent of discussion between the examiners prior to recording their amended final scores. If discussion influences the opinions of an examiner strongly, it is likely there will be higher correlation between examiner scores. To evaluate this effect, independent examiner scores would need to be recorded prior to discussion, with clear guidelines around acceptable amendments to scores.

The finding that the majority of Hot Case variance (63.4%) arises from case variation is consistent with anecdotal reports from examination candidates who describe case difficulty as a “lucky dip”. This finding is consistent with the poor correlation (0.30) between candidates’ first and second Hot Cases. Whilst examiners preview the Hot Case patient, there is no formal method of quantifying and adjusting for the difficulty of each case. According to Kane’s Validity Framework [ 21 ], it is difficult to argue that the assessment is valid if the initial scoring and subsequent generalisation of those scores are based more on case specificity than candidate proficiency, particularly when the implications of the results are significant for candidates and patient safety. The CICM has introduced the Angoff method [ 16 ] for the written examination to account for variation in question difficulty and an appropriate standard setting method for the Hot Case component may mitigate this degree of case variability to some extent. The CICM has avoided the use of norm referenced assessments where candidates are compared with their peers so that all candidates deemed competent are eligible to pass. This is appropriate given the low number of candidates in each sitting, the low number of candidates taken to each case and high variability in case difficulty.

Case specificity is the concept that candidate performance is dependent on the case used and is a major issue in specialist credentialling examinations [ 4 ]. Problem solving ability and clinical reasoning are based on prior clinical experience, areas of particular interest and background knowledge. Candidate performance may be highly case specific, meaning limited numbers of examination cases have detrimental effects on reliability [ 4 , 5 , 22 ]. In the literature, increasing case numbers or overall assessment time is commonly proposed as a method of obtaining more generalisable results [ 6 , 18 , 23 , 24 ]. However, having a candidate pass overall, but clearly fail a component of a credentialling examination may be difficult to justify as defensible from the perspective of patient safety and societal obligations.

The individual examiner Hot Case scores (5.17, SD 1.65) are close to the 50% pass fail boundary. This makes examiners’ decision making difficult, with potentially small differences in performance determining a pass or fail. This is demonstrated in the histogram in Fig.  3 , with a large proportion of trainees scoring a 4.5 or 5, the junction between a pass and a fail. This dichotomisation should be supported by a clear rubric defining what constitutes a minimally competent performance. This will also give candidates clearer performance expectations and may mitigate variability due to case difficulty and specificity by defining expected competencies which are independent of the case difficulty.

Assessing the quality of future care using examination performance as a substitute marker of competence has limitations [ 11 ]. There are concerns from a validity point of view regarding decision making based on short periods of assessment [ 6 , 9 , 10 , 18 , 25 ]. As such, credentialling examinations should focus on identifying low end outliers, a possible true risk to patients and society without further training. Rather than failing candidates with a borderline performance, the focus should be on increasing the sample size to guide decision making. Additional Hot Cases for those with a borderline performance on the oral examination is a possible solution, to increase the reliability for defensible decision making. Summative Hot Cases performed during the training program, but not at the time of the final examination, is another option to increase available data through a transition to a programmatic style of longitudinal assessment.

Restricting the analysis for candidates who sat the written from the 2019-1 sitting onwards was necessitated by the quality of the available dataset. This aided analysis as the Angoff method was introduced for the written paper in 2019 [ 17 ] with the written score no longer counting toward the overall examination score. Candidates are now considered to have passed or failed the written, and then to pass the oral examination they require > 50% from the Hot Case component (worth 30 marks) and viva component (worth 40 marks) combined. This results in a higher benchmark to pass the examination overall, as previously a strong written mark could contribute to an overall pass despite a weaker oral performance.

This research fills a gap in the current understanding of credentialling intensive care physicians. However, it should be taken in context of the overall assessment process. If high stakes assessment requires a reliability coefficient of > 0.8, this value should be the benchmark for the combined oral examination including the Hot Cases and viva component. Further research is required to assess how the Hot Case component and the viva component interact to form the overall reliability of the oral examination.

The strengths of this study include the originality, the predefined statistical plan, the large cohort and the collaboration with the CICM to provide previously unexamined data for an independent analysis. Additionally, the use of descriptive statistics, G-theory analysis and D-studies provides a comprehensive picture of the Hot Case examination reliability in its current format.

Study limitations include dataset consistency issues that restricted the study period, the focus specifically on the Hot Case component without an in-depth analysis of the other components of the examination, the focus on traditional psychometric evaluation and the potential overestimation of examiner calibration due to revision of examiner scores after discussion. Evaluating examination performance without external measures of candidate ability is a research design that focuses on the examination itself. Assessment research is often not truly focussed on candidate competence as this is very difficult to study, so it inevitably evaluates the process rather than the product. As such, identifying poor reliability as a weakness of the Hot Case examination does not detract from potential validity in the overall examination process.

Several implications and unanswered questions remain. Firstly, examiners appear well calibrated, but discussion and score amendment may be significant. Secondly, with additional examiner time, reliability could be increased by challenging candidates with borderline results with additional cases upon which decisions are made. Thirdly, this research highlights the importance of a scoring rubric and robust processes for data capture. Finally, further research is required to assess how the Hot Case and viva examination interact to test the overall reliability of the oral examination. This should be supported by research aiming to assess the validity of the Hot Case as a method of evaluating clinical competence by comparing it with other forms of assessment and workplace competency.

Hot Cases have long been a method of assessment in ICU training in Australia and New Zealand, with perceived benefits from the perspective of stakeholder acceptance and educational impact. Changes to the current examination format to increase reliability would solidify its role in the credentialling process by addressing concerns within the ICU community.

The reliability of the CICM Hot Case examination is less than the generally accepted standard for a high stakes credentialling examination. Further examiner training is unlikely to improve the reliability as the examiners appear to be well calibrated. Modifications to case selection and the introduction of a clear scoring rubric to mitigate the effects of variation in case difficulty may be helpful, but are unlikely to improve reliability substantially due to case specificity. Increasing the number of cases and overall assessment time appears to be the best way to increase the overall reliability. Further research is required to assess how the Hot Case and viva results interact to quantify the reliability of the oral examination in its entirety, and to evaluate the validity of the examination format in making credentialling decisions.

Data availability

The datasets analysed during the current study are not publicly available, but are available from the corresponding author on reasonable request.

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Kenneth R. Hoffman & Chris Nickson

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KH conceived and designed the study, analysed and interpreted the data and drafted and revised the manuscript. DS designed the study, performed the analysis, interpreted the data and revised the manuscript. SL contributed to the conception, design and interpretation of the study and revised the manuscript. CN contributed to the conception, design and interpretation of the study and revised the manuscript. PB contributed to data acquisition and analysis and revised the manuscript. AR contributed to the conception, design and interpretation of the study and revised the manuscript.

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Ethics approval was provided by the University of Melbourne Low Risk Human Ethics Committee (Project number 2022-23964-28268-3). The consent requirement was waived by the University of Melbourne Low Risk Human Ethics Committee as analysis was retrospective using de-identified data with no foreseeable risk to participants in accordance with the Australian National Statement on Ethical Conduct in Human Research 2023.

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KH (Fellow of the CICM), AR (No conflicts of interest), SL (Fellow of the CICM, CICM Second Part examiner 2011-2023, CICM Second Part examination committee 2019-2023, Chair of the CICM Second Part examination panel 2020-2023, CICM First Part examiner 2012-2019), CN (Fellow of the CICM, CICM First Part examiner 2017-2023, CICM First Part examination committee 2019-2023, CICM Supervisor of Training 2018-2023), DS (No conflicts of interest), PB (Employed by the CICM in the position of Information, Communication and Technology Manager).

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Hoffman, K.R., Swanson, D., Lane, S. et al. The reliability of the College of Intensive Care Medicine of Australia and New Zealand “Hot Case” examination. BMC Med Educ 24 , 527 (2024). https://doi.org/10.1186/s12909-024-05516-w

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In the tech world and beyond, new 5G applications are being discovered every day. From driverless cars to smarter cities, farms, and even shopping experiences, the latest standard in wireless networks is poised to transform the way we interact with information, devices and each other. What better time to take a closer look at how humans are putting 5G to use to transform their world.

What is 5G?

5G (fifth-generation mobile technology  is the newest standard for cellular networks. Like its predecessors, 3G, 4G and 4G LTE, 5G technology uses radio waves for data transmission. However, due to significant improvements in latency, throughput and bandwidth, 5G is capable of faster download and upload speeds than previous networks.

Since its release in 2019, 5G broadband technology has been hailed as a breakthrough technology with significant implications for both consumers and businesses. Primarily, this is due to its ability to handle large volumes of data that is generated by complex devices that use its networks.

As mobile technology has expanded over the years, the number of data users generate every day has increased exponentially. Currently, other transformational technologies like  artificial intelligence (AI),  the  Internet of Things (IoT ) and  machine learning (ML)  require faster speeds to function than 3G and 4G networks offer. Enter 5G, with its lightning-fast data transfer capabilities that allow newer technologies to function in the way they were designed to.

Here are some of the biggest differences between 5G and previous wireless networks.

• Physical footprint : The transmitters that are used in 5G technology are smaller than in predecessors’ networks, allowing for discrete placement in out-of-the-way places. Furthermore, “cells”—geographical areas that all wireless networks require for connectivity—in 5G networks are smaller and require less power to run than in previous generations.
• Error rates : 5G’s adaptive Modulation and Coding Scheme (MCS), a schematic that wifi devices use to transmit data, is more powerful than ones in 3G and 4G networks. This makes 5G’s Block Error Rate (BER)—a metric of error frequency—much lower. 
• Bandwidth : By using a broader spectrum of radio frequencies than previous wireless networks, 5G networks can transmit on a wider range of bandwidths. This increases the number of devices that they can support at any given time.
• Lower latency : 5G’s low  latency , a measurement of the time it takes data to travel from one location to another, is a significant upgrade over previous generations. This means that routine activities like downloading a file or working in the cloud is going to be faster with a 5G connection than a connection on a different network.

Like all wireless networks, 5G networks are separated into geographical areas that are known as cells. Within each cell, wireless devices—such as smartphones, PCs, and IoT devices—connect to the internet via radio waves that are transmitted between an antenna and a base station. The technology that underpins 5G is essentially the same as in 3G and 4G networks. But due to its lower latency, 5G networks are capable of delivering faster download speeds—in some cases as high as 10 gigabits per second (Gbps).

As more and more devices are built for 5G speeds, demand for 5G connectivity is growing. Today, many popular Internet Service Providers (ISPs), such as Verizon, Google and AT&T, offer 5G networks to homes and businesses. According to Statista,  more than 200 million homes  and businesses have already purchased it with that number expected to at least double by 2028 (link resides outside ibm.com).

Let’s take a look at three areas of technological improvement that have made 5G so unique.

New telecom specifications

The 5G NR (New Radio) standard for cellular networks defines a new radio access technology (RAT) specification for all 5G mobile networks. The 5G rollout began in 2018 with a global initiative known as the 3rd Generation Partnership Project (3FPP). The initiative defined a new set of standards to steer the design of devices and applications for use on 5G networks.

The initiative was a success, and 5G networks grew swiftly in the ensuing years. Today, 45% of networks worldwide are 5G compatible, with that number forecasted to rise to 85% by the end of the decade according to  a recent report by Ericsson  (link resides outside ibm.com).

Independent virtual networks (network slicing)

On 5G networks, network operators can offer multiple independent virtual networks (in addition to public ones) on the same infrastructure. Unlike previous wireless networks, this new capability allows users to do more things remotely with greater security than ever before. For example, on a 5G network, enterprises can create use cases or business models and assign them their own independent virtual network. This dramatically improves the user experience for their employees by adding greater customizability and security.

Private networks

In addition to network slicing, creating a 5G private network can also enhance personalization and security features over those available on previous generations of wireless networks. Global businesses seeking more control and mobility for their employees increasingly turn to private 5G network architectures rather than public networks they’ve used in the past.

Now that we better understand how 5G technology works, let’s take a closer look at some of the exciting applications it’s enabling.

Autonomous vehicles

From taxi cabs to drones and beyond, 5G technology underpins most of the next-generation capabilities in autonomous vehicles. Until the 5G cellular standard came along, fully autonomous vehicles were a bit of a pipe dream due to the data transmission limitations of 3G and 4G technology. Now, 5G’s lightning-fast connection speeds have made transport systems for cars, trains and more, faster than previous generations, transforming the way systems and devices connect, communicate and collaborate.

Smart factories

5G, along with AI and ML, is poised to help factories become not only smarter but more automated, efficient, and resilient. Today, many mundane but necessary tasks that are associated with equipment repair and optimization are being turned over to machines thanks to 5G connectivity paired with AI and ML capabilities. This is one area where 5G is expected to be highly disruptive, impacting everything from fuel economy to the design of equipment lifecycles and how goods arrive at our homes.

For example, on a busy factory floor, drones and cameras that are connected to smart devices that use the IoT can help locate and transport something more efficiently than in the past and prevent theft. Not only is this better for the environment and consumers, but it also frees up employees to dedicate their time and energy to tasks that are more suited to their skill sets.

Smart cities

The idea of a hyper-connected urban environment that uses 5G network speeds to spur innovation in areas like law enforcement, waste disposal and disaster mitigation is fast becoming a reality. Some cities already use 5G-enabled sensors to track traffic patterns in real time and adjust signals, helping guide the flow of traffic, minimize congestion, and improve air quality.

In another example, 5G power grids monitor supply and demand across heavily populated areas and deploy AI and ML applications to “learn” what times energy is in high or low demand. This process has been shown to significantly impact energy conservation and waste, potentially reducing carbon emissions and helping cities reach sustainability goals.

Smart healthcare

Hospitals, doctors, and the healthcare industry as a whole already benefit from the speed and reliability of 5G networks every day. One example is the area of remote surgery that uses robotics and a high-definition live stream that is connected to the internet via a 5G network. Another is the field of mobile health, where 5G gives medical workers in the field quick access to patient data and medical history. This enables them to make smarter decisions, faster, and potentially save lives.

Lastly, as we saw during the pandemic, contact tracing and the mapping of outbreaks are critical to keeping populations safe. 5G’s ability to deliver of volumes of data swiftly and securely allows experts to make more informed decisions that have ramifications for everyone.

5G paired with new technological capabilities won’t just result in the automation of employee tasks, it will dramatically improve them and the overall  employee experience . Take virtual reality (VR) and augmented reality (AR), for example. VR (digital environments that shut out the real world) and AR (digital content that augments the real world) are already used by stockroom employees, transportation drivers and many others. These employees rely on wearables that are connected to a 5G network capable of high-speed data transfer rates that improve several key capabilities, including the following:

• Live views : 5G connectivity provides live, real-time views of equipment, events, and even people. One way in which this feature is being used in professional sports is to allow broadcasters to remotely call a sporting event from outside the stadium where the event is taking place.
• Digital overlays : IoT applications in a warehouse or industrial setting allow workers that are equipped with smart glasses (or even just a smartphone) to obtain real-time insights from an application. This includes repair instructions or the name and location of a spare part.
• Drone inspections : Right now, one of the leading causes of employee injury is inspection of equipment or project sites in remote and potentially dangerous areas. Drones, which are connected via 5G networks, can safely monitor equipment and project sites and even take readings from hard-to-reach gauges.

Edge computing , a computing framework that allows computations to be done closer to data sources, is fast becoming the standard for enterprises. According to  this Gartner white paper  (link resides outside ibm.com), by 2025, 75% of enterprise data will be processed at the edge (compared to only 10% today). This shift saves businesses time and money and enables better control over large volumes of data. It would be impossible without the new speed standards that are generated by 5G technology. 

Ultra-reliable edge computing and 5G enable the enterprise to achieve faster transmission speeds, increased control and greater security over massive volumes of data. Together, these twin technologies will help reduce latency while increasing speed, reliability and bandwidth, resulting in faster, more comprehensive data analysis and insights for businesses everywhere.

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Judge Merchan faces critical decisions as Trump’s trial nears its end

New York — It’s almost time for the judge to instruct the jury.

New York Supreme Court Justice Juan M. Merchan is approaching a critical juncture in Donald Trump’s hush money trial, one that has tripped up more than a few judges over the years and provided an avenue for defendants to successfully appeal a conviction: the jury charge.

His instructions, given after closing arguments that could come by Tuesday, will be a critical part of the jury’s effort to understand the logic of the prosecution’s case — that falsifying business records constituted felony election interference.

In the first criminal trial of a former U.S. president, it is up to Merchan, a judge for 18 years, to decide how to clearly lay out the legal questions the jury must resolve.

Both sides will supply proposed instructions. Some will come from standardized language devised by the New York courts, but others will be specifically worded to define exactly what the jury must find to convict Trump, the presumptive Republican nominee in this year’s presidential election.

It will fall to Merchan to adopt a suggestion from either side for each instruction, use a standardized version, or write one himself if necessary.

“Jury instructions do have an outsized impact on a trial,” said Renato Mariotti, a defense attorney and former federal prosecutor in Chicago who has been closely following the trial. “Because the jury is going to look at the evidence, and then they’re going to map that evidence to the instructions. Trials are won and lost in the word of specific jury instructions.”

Merchan, 61, has shown an easy confidence in making quick, decisive rulings, even as Trump and his supporters have publicly questioned his impartiality and tried to draw him deeper into the type of political maelstrom that judges typically work hard to avoid.

With cameras barred from court by state law, he is allowing reporters to send written updates on the trial using electronic devices in his courtroom and in an overflow courtroom with a video feed. In an interview before the trial, Merchan told the Associated Press: “There’s no agenda here. We want to follow the law. We want justice to be done. That’s all we want.”

Mariotti said Merchan had done a solid job in managing the trial by promptly picking a jury which has remained intact since the start, issuing rulings which were legally unremarkable, and handling Trump’s violations of a gag order without placing the defendant in jail.

“He has managed to get this almost to the finish line, and that’s no small accomplishment,” Mariotti said.

One key moment came during the detailed sexual testimony of adult film actress Stormy Daniels, which experts said might present a legal pothole for the case if Trump is convicted.

Before Daniels began, Merchan told prosecutors to stay away from explicit details of her alleged sexual encounter with Trump, which the former president denies. The judge said he didn’t want sensational but irrelevant information to taint the jury’s fact-finding in the case, which alleges that Trump falsified records of his reimbursement of Cohen for hush money that Cohen provided to Daniels. Prosecutors say the records classified the reimbursements as legal fees, when they were really a 2016 campaign expense, and that the mislabeling was an effort to keep the payments from becoming public or linked to Trump’s campaign.

New York prosecutors repeatedly asked Daniels for details, however, including whether Trump wore a condom. Defense lawyers objected frequently, though not to the condom question, and Merchan even objected to one question himself, without waiting for the defense. He ordered some of Daniels’ answers struck from the record.

Still, the jury heard Daniels discuss not only Trump’s failure to wear a condom, but also that Trump seemingly blocked her exit before their encounter and her claim to have “blacked out” some of her memories, some of which could be inferred to mean the encounter was nonconsensual, even if Daniels denied that.

Twice, the defense moved for a mistrial, saying Daniels’ testimony was too prejudicial, and too far removed from the business records charges, for a jury to remain unaffected. Merchan denied both motions. “The Court has done everything that I can possibly do to protect both sides and to ensure fairness,” he said.

Mariotti said Merchan “gave the right cautionary instructions to the prosecution in advance. I think the head-scratcher there is why there weren’t more objections from the defense,” a point the judge also made in denying the mistrial motions.

“I don’t think anyone can fault the judge for not jumping in” and objecting to prosecutors’ questions, Mariotti said. “It’s not his role.”

If Trump is convicted, and an appeals court rules that Merchan should have excluded more of Daniels’s testimony and that it could have affected the jury’s verdict, the verdict would be undone. Prosecutors would have to decide whether to retry Trump - a reminder of the importance of Merchan’s management of the case.

The judge is the youngest of six children in a family that immigrated from Colombia to Queens, when he was six years old. He has said he began carrying groceries for tips at age nine and worked as a dishwasher at a diner in high school and as a night manager while he was working on his business degree from Baruch College.

He earned his law degree from Hofstra Law School in 1994; his first job as a lawyer was as an assistant prosecutor in the same Manhattan district attorney’s office that brought the indictment against Trump.

Merchan is no stranger to high-profile cases. In 2012, he oversaw the case of the “soccer mom madam,” a woman charged with running an escort service for wealthy and powerful men. And in 2022, he presided over the trial of the Trump Organization for tax fraud. He is also handling the pending fraud trial of former Trump adviser Stephen K. Bannon, accused of soliciting donations for a border wall with Mexico and then pocketing the money.

While policing his courtroom, Merchan seems well aware of the wider audience watching this particular prosecution. At one point, he spotted Trump cursing under his breath while Daniels was on the witness stand, which wasn’t audible to those sitting behind Trump in the courtroom. The judge called a recess and summoned the lawyers to the bench.

Many judges might have upbraided Trump in front of the courtroom, or even in front of the jury, as a reminder of who’s boss. Instead, Merchan quietly instructed Trump’s lawyers to tell their client to stop his visible reactions, saying he would not tolerate such behavior.

“I am speaking to you here at the bench because I don’t want to embarrass him,” Merchan said.

Each day when court opens, Merchan has looked straight at the defendant and said, “Good morning, Mr. Trump,” a practice he employs in all of his hearings. Unlike most defendants, Trump doesn’t often answer.

The trial has taken Wednesdays off so Merchan can handle the court’s mental health and veterans dockets, in which criminal defendants are placed in rehabilitative programs rather than jail. The judge has overseen this docket for 13 years, and he pays careful attention to each case, speaking directly to each person as he gauges their progress.

“We want you to do well,” he told one defendant recently. “We want you to take advantage of this opportunity.”

For a defendant who’d lost a bag with all of his documents, Merchan instructed a lawyer to help the man acquire a new state identification card. For another, he began by asking the defendant about the New York Knicks, revealing his own passion for the team.

“I can’t watch the games,” Merchan said. “I get too stressed,” though he did know that Knicks’ star Jalen Brunson was “playing lights out.”

Merchan’s level tone rarely wavers, whether he’s discussing counseling appointments with a mental health defendant or doing battle with Trump’s defense attorneys. After the judge called one defense request “absurd,” and attorney Emil Bove began to respond, Merchan said, “Don’t interrupt me.” When Bove protested that he wasn’t interrupting, the judge sternly replied without raising his voice: “No, you are. Have a seat.”

Trump has repeatedly criticized witnesses and others involved in the case, both in public remarks and on social media. Merchan issued an order before the trial telling Trump to stop it.

In the vast majority of criminal cases, that would be the end of the issue. Instead, the “gag order” has become the focus of Trump’s daily diatribes outside the courtroom, as he repeatedly denounces the “corrupt thug” judge - behavior that also is virtually unheard of for defendants.

After Trump falsely declared, “I’m not allowed to testify, I’m under a gag order,” Merchan spoke to him the next day in court, reminding him that the order “restricting extrajudicial statements does not prevent you from testifying in any way.”

Merchan found Trump in contempt of court 10 times, while rejecting four other claims of violations by the prosecutors. He refused the prosecution’s request to let the jury know about his contempt rulings, and he has granted a number of defense motions that limit what evidence the jury will hear.

The judge agreed to block the playing of Trump’s “Access Hollywood” tape to the jury, in which Trump discussed grabbing women’s genitals, saying it was too prejudicial. He also barred prosecutors from referring to Melania Trump having a newborn during some of Trump’s alleged extramarital sexual encounters. The judge forbade the use of Trump’s deposition from his civil sexual assault and defamation lawsuit with writer E. Jean Carroll, though that may change if Trump takes the witness stand.

And though Trump is the only one subject to Merchan’s gag order, the judge last week instructed prosecutors to take their own steps to quiet key witness Michael Cohen, who has freely bashed Trump online while the defendant is prohibited from returning the favor.

On May 6, about midway through the trial, Merchan told Trump he would consider throwing him in jail if he continued to violate the gag order, adding that jailing a former and possibly future president was “the last thing I want to do.”

Merchan, who would have the job of deciding Trump’s sentence if the jury convicts him, said he was “aware of the broader implications” of putting him behind bars for violating the gag order.

He also reminded the defendant who was running this trial.

“At the end of the day, I have a job to do,” the judge said, “and part of that job is to protect the dignity of the judicial system and compel respect … So, as much as I do not want to impose a jail sanction, and I have done everything I can to avoid doing so, I want you to understand that I will, if necessary and appropriate.”