Arising from a medical world confronted to the exponential growth of knowledge required to “exercise clinical judgment”, the perspective of Evidence Based Practice presents itself as a solution to rationalize professional practices in the health and social care field. However, this perspective comprises a few limitations which stem, notably, from a series of methodological reductionisms that must be elucidated to accurately identify what “Evidence Based Practice” may contribute. These reductionisms will be analyzed in the light of the more or less voluntary inscription of the Evidence Based Practice perspective in a new philosophy of public services management.