Low inflation is a larger threat to the U.S.economy.

Janet Yellen in her second public speech since taking the reins at the Fed. Being careful not to talk timing after her "six months" remark in her initial post-FOMC press conference, Yellen said the decision on tightening would hinge on the strength of the labor market and how quickly inflation is headed towards the Fed's 2% goal. She noted wage gains to this point have remained muted, suggesting plenty of slack in the labor market.