A case study design is a qualitative research technique that consists of data collection via a combination of observations, interviews, and/or selected written documents/audiovisual material that is collected and collated for data analysis.
As a distinct approach to research, use of the case study originated only in the early 20th century. The Oxford English Dictionary traces the phrase case study or case-study back as far as 1934, after the establishment of the concept of a case history in medicine. The use of case studies for the creation of new theory in social sciences has been further developed by the sociologists Barney Glaser and Anselm Strauss who presented their research method, Grounded theory, in 1967.
There are multiple types of case studies including: 
- illustrative case studies
- exploratory case studies* critical instance case studies
- program effects case studies
- prospective case studies
- cumulative case studies
- narrative case studies
- medical case studies
- and embedded case studies
The principal use of a case study design approach is to understand a single case or single situation (which could include a small group of people) in significant depth through qualitative observational methods in the case’s natural setting.
Case studies provide a systematic way of looking at events, collecting data, analyzing information, and reporting the results. They are relatively easy to perform and are fairly intuitive. They also are useful in generating and in testing hypotheses.
Limited ability to generalize to other situations outside the specific cases examined and bias.
Examples in Informatics
- Gagnon MP, Duplantie J, Fortin JP, Landry R. Exploring the effects of telehealth on medical human resources supply: a qualitative case study in remote regions. BMC Health Serv Res. 2007 Jan 11;7:6. PMID: 17217534 [PubMed - indexed for MEDLINE]
- Aldrich R, Bonevski B, Wilson A. A case study on determining and responding to health managers' priorities for research to assist health service decision making. Aust Health Rev. 2006 Nov;30(4):435-41. PMID: 17073537 [PubMed - indexed for MEDLINE]
- Bomba D, Land T. The feasibility of implementing an electronic prescribing decision supportsystem: a case study of an Australian public hospital. Aust Health Rev. 2006 Aug;30(3):380-8. PMID: 16879097 [PubMed - indexed for MEDLINE]
- Koppel R, Metlay JP, Cohen A, Abaluck B, Localio AR, Kimmel SE, Strom BL. Role of computerized physician order entry systems in facilitating medication errors. JAMA. 2005 Mar 9;293(10):1197-203. PMID: 15755942 [PubMed - indexed for MEDLINE]
A case study is an in depth look at one or more cases. Case study methodology involves systematically gathering enough information about the “case” (a particular person, social setting, event, group, organization) to allow the researcher to understand how the subject operates or functions and glean insights.1 It is an empirical inquiry that investigates a contemporary phenomenon in a real-life context that is particularly useful when the boundaries between phenomenon and context are unclear.
The case study approach to research can be traced back to sociological fieldwork in the early 19th century.2 Similar methods have been used in medicine. In fact, the fields of medicine and psychology, for example, require physicians and psychologists to examine patients case by case. In addition, case studies are commonly used in business, information systems, and law curricula to help students bridge the gap between foundational studies and practice.1
Case studies can be used in both qualitative and quantitative research. In qualitative research case studies can be:
- Exploratory (to learn more about what is happening in a particular context)
- Descriptive (to provide lengthy, in depth descriptions)
- Explanatory (to explain a phenomenon in a particular context, useful when conducting causal studies)
Case studies can provide a deep understanding of events, people or organizations and can explain complex social phenomena.
The researcher cannot control events and inferences may not always be generalizable. A case can suggest an understanding or explanation in a given context. What is learned may only be transferrable if the study design included multiple cases (which can become expensive).
- Ash JS, Gorman PN, Lavelle M, Payne TH, Massaro TA, Frantz GL, Lyman JA. A Cross-Site Qualitative Study of Physician Order Entry. J Am Med Inform Assoc 2003;10:188-200.
- Koppel R, Metlay JP, Cohen A, Abaluek B, Localio AR, Kimmel SE, Strom BL. Role of Computerized Physician Order Entry Systems in Facilitating Medication Errors. JAMA 2005;293:10,1197-1203.
- Berg, Bruce L. Qualitative Research Methods for the Social Sciences, 6th ed. Pearson, Allyn & Bacon, 2007.
- Crabtree, Benjamin F. and William L. Miller. Doing Qualitative Research, 2nd ed. Sage, 1999.