The increase in the U.S. unemployment rate is mostly a cyclical phenomenon, said researchers at the Federal Reserve Bank of San Francisco, who challenged the view that monetary policy can do little to help.

The researchers, Rob Valletta and Katherine Kuang, discounted the argument made by some, such as Minneapolis Fed President Narayana Kocherlakota, who contend some unemployed workers lack the skills to fill available jobs, a mismatch that can’t easily be fixed with conventional monetary and fiscal policy.

“Analysis of data on employment growth and jobless rates across industries, occupations and states suggests only a limited increase in structural unemployment, indicating that cyclical factors account for most of the rise in the unemployment rate,” the authors wrote in a paper released today.

The U.S. jobless rate stood at 9.6 percent as of October, and more than 8 million jobs were lost as a result of the 18- month recession that ended in June 2009.