The story of the rapid spread of publicly funded pre-kindergarten programs in the U.S. is an education story, to be sure, but it's also a story about the productivity of the work force, closing income gaps, improving health outcomes and so on. The "Economix" columnist for the New York Times, David Leonhardt, wrote a succinct, comprehensive, insightful piece on the Oklahoma pre-kindergarten program the other day--in the business section.

Leonhardt referred to an evaluation done at Georgetown University. Another one, done by the National Institute of Early Education Research, can be found here. Gov. Brad Henry said in his state of the state address this week that he wants to expand the program for four year olds so that it also serves three year olds.