In this paper we considered a missing outcome problem in causal inferences for a randomized encouragement design study. We proposed both moment and maximum likelihood estimators for the marginal distributions of potential outcomes and the local complier average causal effect (CACE) parameter. We illustrated our methods in a real randomized encouragement design study on the e®ectiveness of flu shots.
Zhou, Xiao-Hua; Wang, Richard; and Li, Sierra M., "ITT Analysis of Randomized Encouragement Design Studies with Missing-Data" (March 2005). UW Biostatistics Working Paper Series. Working Paper 245.