Selection of cases and controls is a critical step in the design of a case-control study.
Cases: These are individuals who have the disease or outcome of interest. It is essential to have clear diagnostic criteria to ensure accurate and consistent identification of cases. Controls: These are individuals without the disease or outcome. Controls should be selected from the same population as the cases to ensure comparability. Matching controls to cases on certain variables (e.g., age, gender) can reduce confounding.
