Includes bibliographical references and index.

The importance of causal relationships in medicine and health care -- Study designs which can demostrate and test causation -- The results obtained from studies of causation -- Selection of subjects for study -- Error and bias in observation -- Confounding -- Chance variation -- Combining results from several studies: systematic review and meta-analysis -- The diagnosis of causation -- Critical appraisal of a randomized clinical trial -- Critical appraisal of a randomized trial of a preventive agent -- Critical appraisal of a prospective cohort study -- Critical appraisal of a retrospective cohort study -- Critical appraisal of a matched case-control study -- Critical appraisal of a large population-based case-control study.