The Data: Observational Studies and Sequentially Randomized Trials

Abstract

The data for constructing (optimal) dynamic treatment regimes that we consider are obtained from either longitudinal observational studies or sequentially randomized trials. In this chapter, we review these two types of data sources, their advantages and drawbacks, and the assumptions required to perform valid analyses in each, along with some examples. We also discuss a basic framework of causal inference in the context of observational studies, and power and sample size issues in the context of randomized studies.