SummaryIt has been argued that the routine use of patient-reported outcome measures (PROMs) should be encouraged in order to improve the quality of services and even to determine payment. Clinician-rated outcome measures (CROMs), patient-reported experience measures (PREMs) and process measures also should be considered in evaluating healthcare quality. We discuss difficulties that the routine use of outcome measures might pose for psychiatric services. When outcome and experience measures are used to evaluate services they are difficult to interpret because of differences in case mix and regression to the mean. We conclude that PROMs and CROMs could be useful for monitoring the progress of individuals and that clinical audit still has an important role to play in improving the quality of services.LEARNING OBJECTIVESUnderstand the difference between process measurement and outcome measurement.Understand the limitation of using outcome measures to assess and promote quality of services.Understand the difficulties in assessing the psychometric properties and validity of outcome measures.