On Monday, the Fed announced that labor force participation rates fell slightly below their forecasted value. This is a sign that the U.S. labor market may not be thriving as much as many believe it to be. However, the president of the Chicago Fed believes that many may be lured back into the workforce if job market growth continues.
See "Fed's Evans Says More Workers Could Be Lured Back to Workforce", The New York Times, May 4, 2015