What happens when education adopts medicine’s evidence-based model, and why does the promise of scientific certainty in teaching ultimately undermine educational judgment? This chapter outlines Biesta’s systematic critique of evidence-based practice in education. It looks at the double transformation of research and practice, in which a centrally controlled educational research agenda is set which looks not only at what is researched but also how, and which is then used to reorganise professional practice to make it evidence-based and not educator-determined. The chapter then demonstrates how for Biesta this top-down obsession with ‘what works’ rests on problematic assumptions, including a spectator view of knowledge, a mechanistic causality inappropriate for open social systems, and complexity reduction that tries to transform education into laboratory-like conditions. Following this, the chapter exposes the way in which the discourse of accountability has compounded the issue of evidence-based teaching by shifting its meaning from democratic responsibility to technical-managerial auditing, reducing educational quality to measurable indicators while marginalizing teachers’ professionalism. It then shows how Biesta’s response to this situation is to propose rebalancing education by subordinating instrumental questions of effectiveness (techne) to normative questions of judgement (phronesis). He argues that this should begin in teacher education, replacing the competence-based approach with a virtue-based teacher education that prioritises the formation of educationally wise professionals capable of multidimensional judgment.