Collider bias

1 post

• Confounded dose-response effects of treatment adherence: fitting Bayesian instrumental variable models using brms

  Feb 1, 2018 · 11 min read · R

  Non-randomized comparisons are common in RCTs. In this post I show some examples of confounding and collider bias, using treatment adherence as an example. I present a small simulation study that show that common regression models used in clinical psychology, makes little sense, and that Bayesian instrumental variable regression can be easily fit using the R package brms.