Qian, Klasnja and Murphy provide an assumption that allows for unbiased estimation of treatment effects in microrandomized trials when the data are modeled using linear mixed models with endogenous covariates. In this discussion, the validity of the assumption in the context of the HeartSteps microrandomized trial is reassessed. The utility of a marginal interpretation, versus the proposed conditional-on-the-random-effect interpretation, is also discussed.
"Moving Toward Rigorous Evaluation of Mobile Health Interventions." Statist. Sci. 35 (3) 394 - 395, August 2020. https://doi.org/10.1214/20-STS781