I did not have a good way of expressing how the Fed should convey information after the lift-off until I read the recent paper, "Language after Lift-off: Fed Communication Away from the Zero Lower Bound" by a group of Wall Street and academic economists with a lot of Fed experience. The current policy confusion about communication is caused by the Fed and the market focusing on "time-dependent" messaging when it should be "data-dependent".This paper is a long but worth the effort. Most can read it quickly, but it is filled with little nuggets of important information.
Clearly the forward guidance took a very different tone in the post-financial crisis period. This was the period when the Fed asked about "extended periods". Currently, the language is more focused on data conditions, but there was key focus on time last fall. The move to clear data dependent guidance is critical to helping the markets understand Fed actions.
When the Fed becomes more time dependent, there is less sensitivity to macroeconomic data. During data dependent periods, the market will react more to any new information. If the Fed convinces the market that it is more data dependent, volatility around economic announcements will increase.