Alis Oancea and Richard Pring University of Oxford Department of Education The paper will do three things. First, it will place the "what works" and "systematic reviewing" discourses in the wider contexts of the evidence-base movement; of the recent criticisms of educational research on grounds of relevance and impact; and of research policy emphasis on economic competitiveness, relevance and accountability in the 1990s. Second, we plan to unpick these discourses and explore the understanding of knowledge that they privilege. The set of assumptions and hierarchies so revealed made the models a particularly powerful response to recent policy-originated criticisms of education research. However, while these models may be suitable for some education research, there is a chorus of voices in the profession expressing concerns about their generalisation as the "golden" standard for policy-relevant and policy-recognized research . The final part of our paper will therefore explore challenges to the models discussed. We conclude that, while the systematic accumulation of validated evidence about "what works" may be an effective response to recent criticisms of education research, likely to gain policy endorsement, and also an effective way of discarding certain instances of bad research, at the same time it may be based on narrow assumptions about knowledge that run against what we see as some core principles of education research: critical attitude, diversity, and educational value.