case control study
- noun (written as case-control study)an epidemiological research method in which people who have developed a disease such as cancer are studied alongside people who have not, and the differences and possible causes analysed
- (written as Case control Study)A non-experimental study comparing a series of patients with a particular characteristic of interest (the cases) with a comparison group of patients (controls) who do not have the characteristic in order to determine the effect of exposure to a risk factor. Such studies famously provided the first suggestive evidence of an association between cigarette smoking and lung cancer. Such studies are exposed to the risk of omitted variable bias from unobserved (or even unsuspected) confounders.