Résumé en anglais

The paper aims at addressing the problem of what makes specific aidingto decide within public policy making problem situations. Under such aperspective it analyses some basic concepts such as “public policy”, “deliberation”,“legitimation”, “accountability” and shows the necessity to expandthe concept of rationality which is expected to be behind the acceptability ofa public policy. We then analyse the more recent tentative to construct a rationalsupport to policy making, that is the “evidence-based policy making”approach. Despite the innovation introduced with this approach, we showthat it basically fails to address the deep reasons for which supporting thedesign, implementation and assessment of public policies is a hard problem.We finally show that we need to move one step ahead, specialising decisionaiding methodology to meet the policy cycle requirements: a demand forpolicy analytics.