Non-parametric bounds on treatment effects with non-compliance by covariate adjustment

Abstract

Consider a clinical trial where subjects are randomized to two treatment arms but compliance to the assignment is not perfect. Concerning this problem, this paper derives non-parametric bounds on treatment effects by making use of the observed covariate information. The new bounds are narrower and more informative than the existing ones. In addition, a new non-parametric point estimation approach is proposed based on stratified analysis. Furthermore, to examine the accuracy of estimating the proposed bounds, we provide variance estimators for the proposed approach. The results of this paper can yield credible information on treatment effects, which will be useful for medical research and public health policy analysis. Copyright © 2006 John Wiley & Sons, Ltd.