Case Study: In a case study the survey is based on one or more samples. Study on the respondent(s) can be investigated in depth, which is not possible with large number of sample. In this type of research, the researcher can find out large variety of information about each case specially when very little is known about the subject. 1t is preferred when information in greater details is needed. It probes deep into the factors of interest. The approach is used when a survey with a large sample or an experiment is inappropriate, inadequate, or both.
Case studies can also be made of individuals from certain recognized groups- drug addicts, alcoholics, delinquents, professionals, and subjects belonging to particular ethnic groups, on institutes such as schools, factories, hospitals. It may use past history, description of present events; it could use combination of various methods such as verbal description, observation, measurements, records, and artifacts. The method can also be used to compare a known group with an unknown group.