“Evidence-based policy making” (EBPM) has become a popular term to describe the need for more scientific and less ideological policy making. Some compare it to “evidence-based medicine,” which describes moves to produce evidence, using commonly-held scientific principles regarding a hierarchy of evidence, which can directly inform practice. Policy making is different: there is less agreement on what counts as good evidence, and more things to consider when responding to evidence.Our awareness of these differences between science and policy are not new. Current debates resemble a postwar policy science agenda, to produce more scientific and “rational” policy analysis, which faced major empirical and normative obstacles: the world is not that simple, and an overly technocratic approach to policy undermines much-needed political debate. To understand modern discussions of EBPM, key insights from previous discussions must be considered: policy making is both “rational” and “irrational”; it takes place in complex policy environments or systems, whose properties should be understood in some depth; and it can and should not be driven by “the evidence” alone.
Demography as Social Science and Policy Science