Why do we need evidence-based public policy?

here are three parts to this chapter. The first explains what evidence-based public policy is and the contribution it has made to improving policy design. The second provides a cursory overview of the main techniques used for the empirical analysis of policy outcomes and discusses whether there exists a hierarchy of evidence. The third examines how the principles of evidence-based policy can be extended and protected from threats like fake news, consultants and think tanks synthetically creating whatever data a client might need, and politicians and public servants who have already made up their mind about what works.