ABSTRACT
Emulate a Target Trial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 3.5 The Need for a Unified Analysis of Follow-Up Studies . . . . . . . . . . 114 3.6 A Unified Analysis: G-Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 3.7 Time Zero in Follow-Up Studies without
Baseline Randomization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 3.8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 Appendix 3A.1: Additional Papers That Describe g-Methods and
Related Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . 123 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
ABSTRACT Comparative effectiveness research is concerned with the causal effects of treatments and interventions on health outcomes. We conduct randomized trials and observational studies to estimate these comparative effects and help decision makers-patients, clinicians, payers, and policy makers-decide which interventions to implement. In fact, analyses of observational data for comparative effectiveness research can be viewed as an attempt to emulate a hypothetical randomized trial, which we will refer to as the target trial. This chapter uses the concept of the target trial to outline a unified framework for the analysis of longitudinal studies for comparative effectiveness research, regardless of whether they are randomized or observational.
