Make that three Nobel laureates in economics.

Joseph Stiglitz, an American economist, professor at Columbia University and Nobel laureate in economics, has added his name to the growing list of now-40 economists who endorsed the Employee Free Choice Act via a full-page ad in the Washington Post last week.

The 40 economists - three of whom have received the Nobel prize - have argued that one of the main reasons for our economic slump is the "erosion of workers' ability to form unions and bargain collectively," that shifted the wealth of our country from "broadly-shared prosperity" to "growing inequality."

You can read more about Joseph Stiglitz on his Wikipedia page, and learn more about the project of the Economic Policy Institute here.