Target Trials and Structural Nested Models: Emulating RCTs using Observational Longitudinal Data: Recent Theoretical Empirical Results and Increasing Role in Clinical Medicine

Target trials are RCTs one would like to conduct but cannot for ethical, financial, and/or logistical reasons. Consequently, we must emulate such trials from observational data. A novel aspect of target trial methodology is that, for purposes of data analysis, each subject in the observational study is ‘enrolled’ in all target trials for which the subject is eligible, instead of a single trial. I will describe recent theoretical results connecting target trial methodology and structural nested models. I will discuss a novel inferential conundrum that arises from this connection. If time permits I will also describe how structural nested models can be used for difference in difference analyses with time dependent treatments and confounders.