What Is a Case Study?

Researcher conducting a psychology case study
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A case study is an in-depth study of one person, group or event. Much of Freud's work and theories were developed through the use of individual case studies. Some great examples of case studies in psychology include Anna O, Phineas Gage, and Genie.

In a case study, nearly every aspect of the subject's life and history is analyzed to seek patterns and causes of behavior. The hope is that learning gained from studying one case can be generalized to many others.

Unfortunately, case studies tend to be highly subjective and it is difficult to generalize results to a larger population.

One of the greatest advantages of a case study is that it allows researchers to investigate things that are often difficult to impossible to replicate in a lab. The case study of Genie, for example, allowed researchers to study whether language could be taught even after critical periods for language development had been missed.

In Genie's case, her horrific abuse had denied her the opportunity to learn language at critical points in her development. This is clearly not something that researchers could ethically replicate, but conducting a case study on Genie allowed researchers the chance to study otherwise impossible to reproduce phenomena.

Types of Case Studies

There are a few different types of case studies that psychologists and other researchers might utilize:

  • Explanatory case studies are often used to do causal investigations.
  • Exploratory case studies are sometimes used as a prelude to further, more in-depth research. This allows researchers to gather more information before developing their research questions and hypotheses.
  • Descriptive case studies involve starting with a descriptive theory. The subjects are then observed and the information gathered is compared to the pre-existing theory.
  • Intrinsic case studies are a type of case study in which the researcher has a personal interest in the case. Jean Piaget's observations of his own children are good examples of how an intrinsic cast study can contribute to the development of a psychological theory.
  • Collective case studiesĀ involve studying a group of individuals. Researchers might study a group of people in a certain setting or look at an entire community of people.
  • Instrumental case studies occur when the individual or group allows researchers to understand more than what is initially obvious to observers.

Case Study Methods

There are also different methods that can be used to conduct a case study:

  • Prospective case study methods are those in which an individual or group of people is observed in order to determine outcomes. For example, a group of individuals might be watched over an extended period of time to observe the progression of a particular disease.
  • Retrospective case study methods are those that involve looking at historical information. For example, researchers might start with an outcome, such as a disease, and then backward at information about the individuals life to determine risk factors that may have contributed to the onset of the illness.

    Sources of Information Used in a Case Study

    There are a number of different sources and methods that researchers can use to gather information about an individual or group. The six major sources that have been identified by researchers (Yin, 1994; Stake, 1995) are:

    1. Direct observation: This strategy involves observing the subject, often in a natural setting. While an individual observer is sometimes used, it is more common to utilize a group of observers.
    2. Interviews: One of the most important methods for gathering information in case studies. An interview can involves structured survey-type questions or more open-ended questions.
    3. Documents: Letters, newspaper articles, administrative records, etc.
    4. Archival records: Census records, survey records, name lists, etc.
    5. Physical artifacts: Tools, objects, instruments and other artifacts often observed during a direct observation of the subject.
    6. Participant observation: Involves the researcher actually serving as a participant in events and observing the actions and outcomes.

    More Psychology Definitions: The Psychology Dictionary


    Stake, R. (1995). The art of case research. Newbury Park, CA: Sage Publications.

    Yin, R. (1994). Case study research: Design and methods (2nd ed.). Thousand Oaks, CA: Sage Publishing.

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