title: Stratified analysis in randomized trials with noncompliance.
abstract: This article develops methods for stratified analyses of additive or multiplicative causal effect on binary outcomes in randomized trials with noncompliance. The methods are based on a weighted estimating function for an unbiased estimating function under randomization in each stratum. When known weights are used, the derived estimator is a natural extension of the instrumental variable estimator for stratified analyses, and test-based confidence limits are solutions of a quadratic equation in the causal parameter. Optimal weights that maximize asymptotic efficiency incorporate variability in compliance aspects across strata. An assessment based on asymptotic relative efficiency shows that a substantial enhancement in efficiency can be gained by using optimal weights instead of conventional ones, which do not incorporate the variability in compliance aspects across strata. Application to a field trial for coronary heart disease is provided.
authors.affiliation: Department of Pharmacoepidemiology, School of Public Health, Kyoto University, Kyoto 606-8501, Japan. matsui@pbh.med.kyoto-u.ac.jp
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Matsui
mesh_terms: D002784:Cholesterol / Q000097:blood; D003327:Coronary Disease / Q000517:prevention & control; D003627:Data Interpretation, Statistical; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D016540:Smoking Cessation; D016312:Treatment Refusal
chemical_list: D002784:Cholesterol