Indeed, in our September FOMC statement, we indicated that we expect it will be appropriate to keep the federal funds rate in the current 0 to 25 basis point target range until inflation has reached 2 percent (on an annual basis) and labor  The Statement on Longer-Run Goals and Monetary Policy Strategy articulates this concept with the following: “The maximum level of employment is a broad-based and inclusive goal that is not directly measurable and changes over time owing largely to nonmonetary factors that affect the structure and dynamics of the labor market.
Well, first of all, most central banks have linked forward guidance to their main policy interest rates. In implementing their monetary policy, central banks calibrate their main policy tools so as to establish a certain level of short term interest rates in the market.