The past decade has seen a largely unquestioned view that public policy should be evidence-based. And who could question it anyway? It seems so obvious.

But it has not been a completely smooth journey. There have been times when it feels more like policy-based evidence-making, as researchers have desperately sought for data that can be used to justify a pre-determined course of action. Then there is the time it takes. And the cost! Then how often have we heard our more practical colleagues complain that much of the evidence is too theoretical, or hypothetical.