I think we have great science expertise in this country. Policy-makers need to listen more to that expertise and not try to invent new measures. If they're unhappy with the measures, tell the scientists what they would like to measure to achieve their public policy targets. Make sure the two are matched. But don't fool yourself with trying to measure this number when in fact your policy target is for something else.
On May 7th, 2013. See this statement in context.