The Super Bowl stirred up an old controversy in the international aid community.  What happens to all those preprinted “Pittsburgh Steelers 2011 Super Bowl Champion” t-shirts?  Apparently, each year the NFL gives them to the international relief and development organization World Vision, who then ships them to Africa.

Is this good or bad? And why should anyone care?

Dean Karlan explains all in a guest post on the Freakonomics blog.