This paper contributes to the theory of active comparators in clinical research. We discuss attempts to minimize bias in observational studies by using a comparator group consisting of individuals who initiate a drug unrelated to the outcome of interest, and clarify the conditions under which this approach leads to valid inferences.
Recommended citation: ‘Huitfeldt A, Hernan MA, Kalager M, Robins JM. "Comparative effectiveness research using observational data: Active comparators to emulate target trials with inactive comparators". eGEMs: Vol. 4: Iss. 1, Article 20.’