Comment: On the Potential for Misuse of Outcome-Wide Study Designs, and Ways to Prevent It

We congratulate the authors, VanderWeele, T.J., Mathur, M.B. and Chen, Y. (2020) (hereafter referred to as VMC), for making an interesting and important proposal, and thank the Editor for the opportunity to comment on it. We agree with VMC that outcome-wide epidemiology has the potential to overcome many of the weaknesses of the traditional epidemiological approach. Scientific reports that express the effects of exposure on a variety of different outcomes provide a more complete view on the exposure impact, while lessening the risk of selective analysis and reporting. We see much value in it, though caution is warranted. In this commentary, we highlight a number of key limitations, which will in turn suggest preferred analysis strategies that we find important to consider in addition to (or instead of) those described by VMC.