What works centre for local economic growth

I wrote yesterday about the problem with Portas Pilots, arguing that the way the scheme was implemented will make it almost impossible to figure out whether the projects actually have an impact. This is just one example of a more general failure - government is often very bad at generating convincing evaluation evidence and (arguably) even worse at using that evidence to inform policy making. Could a NICE for social policy help fix this? It appears that we may be about to find out as the government has announced the establishment of four 'What Works centres' covering the areas of crime, ageing, early intervention and local economic growth.