Do elementary school teachers need master’s degrees

From the Chronicle of Higher Education:

In a speech at an American Enterprise Institute forum on Wednesday, the secretary of education, Arne Duncan, said state and local governments should rethink their policies of giving pay raises to teachers who have master’s degrees because evidence suggests that the degree alone does not improve student achievement.

This is a familiar territory in this blog; back in September 2009, I blogged, citing Matt Yglesias, questioning the logic behind paying teachers more if they have graduate degrees.  It adds on a huge cost to taxpayers, with no returns on this premium.