Public policy is the principled guide to action taken by the administrative executive branches of the state with regard to a class of issues, in a manner consistent with law and institutional customs. There has recently been a movement for greater use of evidence in guiding policy decisions. Proponents of evidence-based policy argue that high quality scientific evidence, rather than tradition, intuition, or political ideology, should guide policy decisions. Public policy is the principled guide to action taken by the administrative executive branches of the state with regard to a class of issues, in a manner consistent with law and institutional customs. There has recently been a movement for greater use of evidence in guiding policy decisions. Proponents of evidence-based policy argue that high quality scientific evidence, rather than tradition, intuition, or political ideology, should guide policy decisions.