Scores on patient-reported outcomes (PROs) in a treatment setting must convey clinical meaning and understanding to be useful. As stated in the FDA PRO Guidance for Medical Product Development, one way to lend meaning and interpretation to a quantitative PRO measure is to dichotomize between values where within-patient changes are considered clinically important and those that are not. But even a PRO scale with a cutoff score that discriminates well between responder and non-responders is fraught with some misclassification: Some individuals classified as responders (based on the cutoff or threshold score on the PRO measure) may in fact be non-responders; some individuals classified as non-responder may, in fact, be responders. In this presentation, formulas are provided that correct for such responder misclassification under the assumption of no treatment misclassification. Estimates of treatment effect are compared between unadjusted and adjusted estimates of treatment effect. Two case studies from sexual medicine illustrate the methodology. Limitations of the methodology are noted.