A case-control study is a type of observational research used to identify factors that may contribute to a specific outcome, such as a disease. In this study design, researchers compare two groups: those who have the outcome of interest, known as the cases, and those who do not, called the controls. By examining the differences in exposure to potential risk factors between these groups, researchers can infer associations that may help understand the causes of the outcome. These studies are particularly useful for studying rare diseases or outcomes because they start with the outcome and look backward in time to find possible causes. They often rely on existing records or interviews to gather information about past exposures. While case-control studies can suggest associations, they do not establish causation, and results must be interpreted with caution.