Statistical evaluation of surrogate markers: Validity, efficiency, and sensitivity

Abstract

Identification of surrogate markers for a marketed drug is important in monitoring the efficacy or safety after a patient uses the drug. In this article, we clarify the statistical definitions of the surrogate endpoint and surrogate marker and introduce the concept of the validity and efficiency of a surrogate marker. We also review some existing methods and suggest the proportion of information gain is appropriate to be used to evaluate the validity of a surrogate marker.