CLARITY OVERRATED?: For U.S. policy makers, events that seem at first like positive developments can sometimes unexpectedly bite back.

CLARITY OVERRATED?: For U.S. policy makers, events that seem at first like positive developments can sometimes unexpectedly bite back.

UNEXPECTED TAKEAWAY: Federal Reserve Chairman Ben Bernanke suggested last week that continued economic gains might allow the central bank to begin withdrawing financial life supports "later this year." It may have sounded like good news, but it triggered a multiday sell-off in the stock and bond markets.

OBSCURITY MAY WORK: The previous two Fed chairmen Alan Greenspan and Paul Volcker often seemed deliberately obscure when discussing Fed strategy. It wasn't always clear what they meant. But their public comments rarely triggered huge market selloffs either.