Which type of research involves an in-depth analysis of a single individual or group?

The type of research that involves an in-depth analysis of a single individual or group is known as a case study. Case studies are particularly valuable in psychology because they allow researchers to gather detailed insights and data about a particular subject or phenomenon over an extended period. This method can uncover unique nuances and complexities that larger-scale studies might overlook.

For instance, case studies can help illuminate the behaviors, motivations, and experiences of an individual or a small group, providing a rich narrative that contributes to the understanding of psychological concepts. This approach is often used when a phenomenon is rare or not well understood, thus requiring a deep dive to explore the intricacies involved.

In contrast, survey research typically collects broad quantitative data from larger populations but lacks the depth and contextual understanding achieved in case studies. Longitudinal studies involve observing changes over time, which can also provide useful data but still do not focus on the depth of a single case. Experimental research is designed to test specific hypotheses and establishes relationships through manipulation, which is fundamentally different from the descriptive nature of case studies.