Adaptive Case-Control Study — Adaptive Observational Epidemiological Design

An adaptive case-control study is a case-control design that incorporates pre-specified rules allowing modification of study parameters — such as sample size, case-to-control ratio, or matching criteria — based on interim data, without compromising validity. It combines the efficiency of adaptive methodology with the retrospective exposure-ascertainment logic of classical case-control research, enabling investigators to respond to emerging evidence while the study is ongoing.