That´s because it can´t be simply called “policy”. Over time the Fed´s economic growth projection has been falling, and after it drops a few notches the Fed introduces something “new” (or “surprising”).
What happens when you get to the “zero growth projection”? Last year Mark Carney ventured that forward guidance with thresholds was the “last resort” and “If yet further stimulus were required, the policy framework itself would likely have to be changed. For example, adopting a nominal GDP level target could in many respects be more powerful than employing thresholds under flexible inflation targeting.”
My question: Why wait for the lower bound for the growth projection to hit zero?