A case study is an in-depth investigation of a single event, group, or individual. Investigators gather data through different sources, which may include direct observation, interviews, focus groups or surveys. Data collection is often qualitative. Investigators will then offer an analysis.
Unlike experiments, where researches often control for different variables, case studies are detailed investigations into real life phenomena.
Case studies are commonly used in these areas of research:
What is a case study and how to conduct case study research by Research Tube.
Case studies help researchers understand, evaluate, compare, and describe their research problem. Comprehensive case studies also offer a holistic view, which helps contextualize a research problem. In addition, a good case study will reduce bias and personal agendas by featuring a range of perspectives and opinions. However, case studies shouldn't be used to make broad generalizations.