The Federal Reserve is studying how the current crisis may have affected U.S. economic productivity and how those changes may have affected the difference between how the economy grows and its full potential, Fed Vice Chairman Donald Kohn said on Saturday.

The effect of the crisis, the shifting of labor across markets, the effects on productivity have been very much one of the topics at the Fed, Kohn said in response to questions after a conference at Princeton University.

Right now, there's no question in my mind there's a very substantial output gap, he said.