Q.Discuss the strengths and limitations of the case study method as a tool of psychological research.

The case study method centres on an in-depth, detailed investigation of one particular 'case', which may be a single individual with some distinguishing characteristic, a small group sharing something meaningful in common, an institution, or a specific event, chosen precisely because it can offer critical insight into a phenomenon that is not yet well understood. Its central strength is depth: because a case study typically draws on multiple methods at once, interview, observation, and psychological testing, gathered from a range of respondents connected to the case, it can generate an unusually rich, detailed and holistic account of a person's or a group's experience, uncovering nuances that a large-sample survey or a tightly controlled experiment, both of which trade depth for breadth, would never pick up. This is exactly why case studies have proven historically valuable in clinical psychology and human development, Freud's psychoanalytic theory grew directly out of meticulously recorded observations of individual patients, and Piaget's theory of cognitive development grew out of careful, detailed observation of his own three children. The case study's central weakness is generalisability: because the case or cases selected for study are, by definition, unique, it is genuinely difficult to establish that a conclusion drawn from a single case would hold true for people, groups or situations in general, the very depth that makes a case study valuable also makes it hard to know how far its findings can be safely extended beyond the specific case studied, which is the essence of the problem of validity in case-study research. Good practice for managing this weakness includes drawing on multiple sources and methods of information rather than a single one, involving more than one investigator wherever practical, and maintaining a careful, documented chain of evidence linking every piece of collected data back to the actual research question.