Context: Debate exists on overactive bladder (OAB) treatment-response assessment in clinical trials and the nature and shortcomings of the different endpoints used in OAB clinical research. Objective: To evaluate current evidence and tools that measure OAB treatment response in clinical trials and to inform the development of a new multidimensional patient-reported outcome (PRO) that could be used as a primary endpoint in OAB trials. Evidence acquisition: We conducted a narrative review of OAB literature available in the PubMed database published between January 1, 2004 and June 30, 2015. Eighty articles were selected for full text review. Evidence synthesis: The assessment of treatment outcomes in OAB is challenging due to the heterogeneity of symptoms and reliance on PROs. OAB studies report a high level of placebo effect and the placebo response is poorly understood. We found significant correlations between PRO measures and bladder diaries. There is evidence of several issues with the bladder diary: burden, over/underestimation, recall period, and lack of validation. Trials for other conditions-interstitial cystitis, benign prostatic hyperplasia, headache, and restless legs syndrome-have used symptom scales rather than diaries to measure treatment outcomes and some now incorporate PRO measures as primary, coprimary, and secondary endpoints. The International Consultation on Incontinence Research Society recommends evaluation of satisfaction, symptoms, health-related quality of life, and adverse events. Conclusions: There is strong evidence of the shortcomings in current approaches to measuring OAB outcomes in clinical trials and recognition that a new simpler approach which incorporates symptom and health-related quality of life assessment could provide a more comprehensive, standardized approach to OAB assessment. Patient summary: Overactive bladder is a urinary syndrome. Individuals experience different symptoms to varying degrees, which poses difficulties in accurately measuring the effect of treatment. This review found evidence and recommendations that propose a simpler but more comprehensive way to measure treatment outcomes. (C) 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.