The selective promotion of clinical services which have proven effectiveness is a movement that is gaining momentum within healthcare. Outcome evaluation in treatment services for alcohol dependency is given as an example of the methodological issues associated with the establishment of clinical efficacy. It is argued that the adoption of clear protocols for assessment, treatment and outcome are a prerequisite of the process. There are costs associated with in-house follow-up studies but the benefits of feedback are evident for patients and for staff providing their care. Although exposing service providers (and commissioners) to the possibility of negative feedback, outcome evaluation in the treatment of alcohol dependency should be an integral part of provision. The principle of systematic assessment of efficacy applies to healthcare provision generally and should include management, teaching, purchasing and policymaking.