Five different research designs are used in sociological research: A case study research design is one that focuses on the detailed analysis of a single case or situation, usually a community or organization, in a specific location. The participant observation approach usually involves researchers who immerse themselves over a period of time in the social setting or context. Their goal is to observe, listen to, and gather information on the social life and culture of the people they are studying. Longitudinal studies involve two or more case studies of the same units of analysis with a certain amount of time between the studies. analysis with a certain amount of time between the studies. Longitudinal studies occur in a number of circumstances: When the researcher remains a member of, or participant in, the community under study for a period of several months or years.