title: Power, sample size and smallest detectable effect determination for multivariate studies.
abstract: This paper discusses some general methods for determining approximate power, sample size, and smallest detectable effect for studies of multiple risk factors. These methods are based on standard large-sample formulae for determining the power of chi-square tests, and emphasis is given to determinations for Pearson chi 2 tests in multiway contingency tables. The methods are illustrated in application to the design of a clinical trial of the preventive effect of alpha-tocopherol, ascorbic acid and beta-carotene on colon polyp recurrence, and a case-control study of the joint effect of smoking and asbestos exposure on lung cancer incidence.
mesh_terms: D001699:Biometry; D002986:Clinical Trials as Topic / Q000379:methods*; D003111:Colonic Polyps / Q000188:drug therapy; D004812:Epidemiologic Methods; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology; D012008:Recurrence