The main purpose of this article is to question the relevance of the Randomised Controlled Trial for the evaluation of health promotion programmes. In its concern to manage Type 1 error, the RCT underestimates or virtually ignores Type 2 and 3 errors. Because of the peculiar complexities of health promotion programmes and the importance of gaining insights into the effect of interventions--rather than merely recording whether or not they achieve their goals--a new kind of validity is needed. The central assertion here is that we should adopt a principle of "judicial review" which is based on a broad spectrum of triangulated evidence.