Introduction Definition A case-control study is a design in which individuals with an event or condition of interest CASES, are identified and then compared with regard to one or more exposures to individuals without the event or condition of interest CONTROLS Case-control investigations typically are designed to assess the association between occurrence of disease and an exposure suspected of causing(or preventing) that diseaseDefinition A case-control study is a design in which individuals with an event or condition of interest, CASES, are identified and then compared with regard to one or more exposures to individuals without the event or condition of interest, CONTROLS. Case-control investigations typically are designed to assess the association between occurrence of disease and an exposure suspected of causing (or preventing) that disease. Introduction