What central banks may have the world over is a failure tocommunicate.

Officials are struggling to spell out their visions for monetarypolicy, often amid a chorus of competing views. Chairman Ben S.Bernanke is trying to manage expectations about when the U.S.Federal Reserve will slow asset purchases and raise interest rates.Bank of Japan Governor Haruhiko Kuroda's reflation-push isbackfiring by driving up bond yields. European Central BankPresident Mario Draghi is dashing investors' hopes he once kindledfor extra stimulus.

The muddied messaging already is roiling financial markets,threatening to undermine the confidence of investors, households,and consumers and so undoing efforts by central banks to strengthentheir economies. The opacity puts policy makers under pressure toimprove the communication techniques they've been using to restrainborrowing costs.