The Cochrane/Campbell collaboration and the setting up of evidence based centres for educational research are based on the notion of research syntheses (an idea with many merits and some problems, Gorard 2001a). Research can then be used as a basis for establishing ‘evidence based’ practice where pedagogical and other decisions are guided by nationally agreed ‘protocols’ (as in the field of medicine, Department of Health 1997). Syntheses of high quality studies are used to produce the findings, which are then…