A case study is a research methodology that has commonly used in social sciences. A case study is a research strategy and an empirical inquiry that investigates a phenomenon within its real-life context. Case studies are based on an in-depth investigation of a single individual, group, or event to explore the causes of underlying principles. A case study is a descriptive and exploratory analysis of a person, group, or event. A case study research can be single or multiple case studies, includes quantitative evidence, relies on multiple sources of evidence, and benefits from the prior development of theoretical propositions. Case studies are an analysis of persons, groups, events, decisions, periods, policies, institutions, or other systems that are studied holistically by one or more methods.