A case study is a detailed analysis of an individual, group or event that examines their characteristics and behavior through a systematic observation and evaluation. It can be used to explore complex issues in depth, by presenting a complete picture of the subject matter using various sources of information such as interviews, surveys, records, and direct observations. Case studies are commonly used in academic research, business analysis, psychology, sociology, medicine, and other fields that require an in-depth understanding of specific situations or phenomena.