What is the difference between a case-control study and a cross-sectional study?

Case-control and cross-sectional studies differ in how participants are recruited and the types of questions they can answer.

In a case-control study, participants are recruited based on outcome status. Data are collected from two groups. The “case” group has an outcome of interest (e.g., a diabetes diagnosis), and the “control” group does not. These groups can be compared to understand what differences may have contributed to the outcome.

In a cross-sectional study, a sample of participants is recruited from a population without considering outcome status (often using random sampling). Data on outcomes and risk factors are then collected simultaneously from the sample. Cross-sectional studies are helpful for assessing the prevalence of an outcome.