Using randomised controlled trials (RCTs) to test service interventions: issues of standardisation, selection and generalisability.

The commissioning of healthcare services is increasingly linked to the availability of rigorous evidence of clinical and cost effectiveness. In the current climate, 'rigorous evidence' is synonymous with the randomised controlled trial (RCT). Consequently, health technologies are often funded in preference to service developments due to an imbalance in the availability of strong evidence to support service developments.