The region most at risk is the 17-nation euro area, where banks are deleveraging and wages are falling in nations including Spain. The ECB already is turning more aggressive after inflation slumped to a four-year low of 0.7 percent in October, less than half its target of just below 2 percent. Prices may not pick up any time soon, Draghi has warned. Unemployment is a record 12.2 percent, and the European Commission said last week it anticipates growth of just 1.1 percent in 2014.

“Deflation is not imminent, but it has to be on the mind of central bankers,” ECB Governing Council member Ewald Nowotny said yesterday in Vienna.

The central bank still needs to do more because “a ‘Japanification’ of the euro area is a clear and present danger,” Joachim Fels, co-chief global economist at Morgan Stanley in London, said in a Nov. 10 report to clients.

Avoiding that fate may be hard. While Draghi has raised the possibility of charging banks to park cash at the ECB, colleagues have warned a negative deposit rate could hurt banks’ profitability and make them even less willing to lend.

Fed-style quantitative easing also has been ruled out, given the ECB is barred by European Union treaties from financing state debt. Still, policy makers have room to cut their benchmark more and also haven’t announced whether they will again lend money to banks for long periods of time.

Japan shows that “because inflation is very slow-moving, once you get in the liquidity trap, you have to move fairly forcefully to get out and to get inflation up,” said Kenneth Rogoff, a professor at Harvard University in Cambridge, Massachusetts, and a former IMF chief economist.

The Fed has found that expanding its balance sheet -- now at a record $3.85 trillion -- hasn’t been a panacea. Since the U.S. recession ended in June 2009, growth has fallen short of its predictions, and in nine of the last 10 estimates for 2013, policy makers have lowered their forecasts. The central tendency -- which excludes the three highest and three lowest projections -- now shows growth of 2 percent to 2.3 percent, compared with 3.5 percent to 4.3 percent in April 2011.

Stay Low

Inflation, too, is lower than projected and has undershot the Fed’s 2 percent target starting in May 2012. The personal- consumption-expenditures index, the board’s preferred gauge, increased 0.9 percent in September from a year earlier, matching April for the lowest since October 2009. The rate will stay low in 2014, at about 1.25 percent, according to Sinai.

Bernanke said in June he viewed the slowdown as reflecting “some factors that are likely to be transitory.” The ensuing months have complicated the Fed’s strategy and challenged the notion that underlying demand would boost prices in the second half of the year.