Investors trying to pinpoint when the Federal Reserve will end its bond-buying program shouldn't waste their time trying to figure out the timeline, according to researchers at regional Federal Reserve banks. 

More crucial in terms of monetary policy's impact on growth and inflation will be signals from the Fed on when it will start to raise short-term interest rates from near-zero level.

"Our analysis suggests that communication about when the Fed will begin to raise the federal fund rates from its near zero-level will be more important than signals about the precise timing of the end of of QE3," San Francisco Fed senior economist Vasco Curdia and New York Fed senior economist Andrea Ferrero wrote.