Nobel Prize–winning economist Joseph E. Stiglitz found himself stumped. Last February, speaking by video link to the Scottish Parliament’s economy committee, Stiglitz was asked by a lawmaker what he thought of the Legatum Prosperity Index. “Uh, I’m not sure I know the detail,” replied the baffled Columbia University professor. “There are a lot of indices out there.”

A version of this article appeared in the September 2013 issue of Harvard Business Review.