In a case-control study, two groups of people are compared.

They showed a statistically significant association in a large case-control study.

Case-control studies are therefore placed low in the hierarchy of evidence.

Recall bias is always a problem in case-control studies of cancer.

Because case-control studies are usually based on individual-level data, they do not have this problem.

It can be more expensive than a case-control study.

We report here the results of a case-control study set up to investigate whether the excess was related to parents' employment in the nuclear industry.

Diet and cancer of the prostate: a case-control study in Greece.

One or more case-control studies should be nested within the cohort study.