Authors' reply: Letter to the Editor: Comparison of statistical approaches dealing with time-dependent confounding in drug effectiveness studies (SMMR, Vol 27, Issue 6, 2018) ME Karim, J Petkau, P Gustafson, RW Platt January 2019 Source Document marginal-structural-model simulation causal-inference Related Comparison of statistical approaches dealing with time-dependent confounding in drug effectiveness studies Estimating inverse probability weights using super learner when weight-model specification is unknown in a marginal structural Cox model context On the application of statistical learning approaches to construct inverse probability weights in marginal structural cox models: hedging against weight-model misspecification Comparison of statistical approaches for dealing with immortal time bias in drug effectiveness studies Can we train machine learning methods to outperform the high-dimensional propensity score algorithm?