The Federal Reserve's Plan - We Don't Know What We Are Doing But We Are Committed To Doing More Of It

Yellen said that the wisdom of the Fed's approach is now the subject of "considerable debate." "With economic activity weakening, economic slack is likely to be substantial for several more years," she said.

Yellen admitted that it was hard to prove that the new programs were working.
"We simply don't have the experience needed to pin down the magnitude of the impacts," she said, but added that this was just another argument in favor of a broad, aggressive, approach.

When I'm riding in a 747 jumbo jet, I am usually comforted by the fact that the pilot isn't flying blind.