Glossary of statistical terms

Case-control study: In a case-control study we take a group of people with the disease, the cases, and a second group without the disease, the controls. We then obtain information for each subject concerning exposure to possible causative factors and look for differences in exposure between the two groups. The way in which we select controls is obviously very important. We want a group of subjects that do not have the disease under study but who are otherwise comparable to our cases. The design is usually retrospective (relating current disease status to past exposures).