What does the term "case-control" indicate in a study design?

The term "case-control" in study design refers specifically to a type of observational study that compares individuals with a specific condition or disease (the "cases") to those without the condition (the "controls"). This design is particularly useful for looking at the association between exposures and outcomes by assessing whether the cases were more likely than the controls to have been exposed to certain risk factors.

In case-control studies, the focus is on the disease status, where individuals are selected based on whether they have the disease of interest or not, without consideration of how they were exposed. This means researchers start with the outcome (the disease) and then look backward to assess exposures, allowing for the efficient study of rare diseases or outcomes.

The other options describe different study designs. Randomly assigning participants to treatment or control groups is characteristic of a randomized controlled trial. Measuring drug efficacy in a cohort pertains to a cohort study where groups are followed over time based on exposure status to determine outcomes. Following participants over time indicates a longitudinal study, which monitors the same individuals over a specified period.