title: A simple estimator of minimum detectable relative risk, sample size, or power in cohort studies.
abstract: In planning simple cohort mortality studies, researchers need to know what size of relative risk may be confidently detected with the projected size of the cohort and length of follow-up. Although methods for the calculation of such minimum detectable risks have been devised for case-control studies and for cohort studies where internal comparisons are the focus, this has not been explicitly done for cohort studies using external comparisons. This paper describes a simple procedure designed explicitly for investigating the adequacy of cohort size at the planning stage of a study. An example is presented of a retrospective cohort study of men in a Canadian factory. A method is shown for estimating the minimum detectable underlying relative risk for lung cancer in this cohort.
mesh_terms: D000328:Adult; D004812:Epidemiologic Methods; D006801:Humans; D007221:Industry; D008175:Lung Neoplasms / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000401:mortality*; D011336:Probability; D012189:Retrospective Studies; D012306:Risk