Case Study

A case study is a research technique used to study an individual or group providing intense description and analysis. This particular method was the cornerstone of Freud’s work in his psychodynamic theory; his classic case study of “Little Hans,” a child terrified of horses, was used to demonstrate how psychological difficulties of an individual can be interpreted to explain basic psychological and developmental processes. Case studies, however, are not limited to pathology; Piaget used the intense observation characteristic of the case study with his own children to develop his stage theory of cognitive development. Additionally, case studies are not limited to the individual. Study of a group, even if large, offers insights into the impact of various cultural and historical events. For example, studying the coping of the rescue workers, survivors, and witnesses on the scene of the Murrah Building bombing in Oklahoma City provided mental health professionals a starting point when they arrived on the scene of the World Trade Center attacks.

The best understood advantage of the case study is the opportunity to study rare phenomena. For example, genius in children is often studied using case studies. Case study can offer valuable insights into the parameters of giftedness in children and, for example, its impact on social behavior.

A second advantage is that case studies of people in extreme circumstances offer an opportunity for developmental researchers to address questions that would be unethical to study otherwise. For example, a central question in language development is whether a critical period exists: do children have to be exposed to language by puberty to develop language? “Genie” was approximately 13 when she was found by social services, having had virtually no human contact or exposure to language since she was 2.

Genie’s case demonstrates the third and perhaps most powerful advantage of the case study. The case study offers the possibility of challenging a theory if it violates a critical, general proposition of the theory. Because  Genie was capable of developing some language, her case offered a refutation of the absolute view of the critical period theory that language would not be acquired at all without exposure during this critical period.

The disadvantages of the case study method are threefold. First, there is typically a considerable lack of control in the case study, usually because nature provides the arrangements rather than a researcher. For example, Genie suffered such extreme emotional deprivation that her failure to develop normal language cannot be solely attributed to the critical period theory.

Second, the ability to generalize from a case study is limited. If the researcher is investigating developmental phenomena that are considered to vary from one individual to another, such as personality, it is impossible to claim that a case study of one individual is representative of others.

Third, the data collection process itself in case studies is open to bias and distortion, albeit unintentional. Much case study data come from archival data and observation. It is difficult to avoid systematically recording those events and behaviors that are consistent with the hypothesis being investigated. However, it is important to note that this disadvantage is by no means limited to the case study.

In conclusion, it is important to understand both the benefits and problems of the case study methodology. The case study method is typically considered an exploratory method useful for generating new hypotheses but hampered by issues of generalizability and control. Case studies are perhaps best thought of as complementary to the other research methodologies as opposed to an inferior alternative


  1. Shaughnessy, J. J., Zechmeister, E. B., & Zechmeister, J. S. (2003). Research methods in psychology (6th ). New York: McGraw-Hill.
  2. Tellis, W. (1997,  September). Application  of  a  case  study methodology. The Qualitative Report [On-line serial], 3(3). Retrieved from http://www.novedu/ssss/QR/QR3-3/tellis2.html