Though the U.S. central bank renewed its commitment last week to buy $85 billion in bonds per month and to keep rates low for some time to come, weaker inflation on the one hand and a steady drop in unemployment on the other have investors anxiously guessing when monetary policy will shift.
Philadelphia Fed President Charles Plosser, a policy hawk and unlike Evans not a voting member of the Fed's policy committee this year, took the opposite tack and called the effects of the bond-buying program "dubious."
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"I've never felt that our asset purchases have been that effective in addressing what's the biggest problem we face in this country, which is the employment market and the labor market," he told Bloomberg television separately on Tursday.
"I'd like to stop but I would particularly like to see us begin to slow the pace down, gradually ease our way out of this if we possibly can."
Later on Thursday, Plosser told reporters in New York that he is "not too concerned" about weaker recent U.S. inflation readings, arguing the Fed should move to stave off disinflation only if expectations begin to fall.
"I do believe we have to defend our inflation target (of 2 percent) both on the upside and the downside and it's important to do so," he added. "But as long as inflation expectations remain well anchored I'm reasonably comfortable."
Strong differences of opinion among policymakers at the U.S. central bank are not unusual, and Plosser and Evans in particular have long sparred from opposite ends of the policy spectrum.
Investors will be watching closely for any hints from Fed Chairman Ben Bernanke about his policy outlook when he gives a speech at the Chicago Fed on Friday.
Unemployment fell to 7.5 percent last month, continuing a steady but slow three-year decline, and last week the number of Americans filing new claims for unemployment benefits dropped to its lowest level in nearly 5-1/2 years.
But other economic signals have been less encouraging, including inflation that has dropped now to about half the Fed's 2-percent target.
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Low inflation has in fact prompted one policymaker, St. Louis Fed President James Bullard, to suggest the Fed may need to add to its stimulus to defend the economy against a possible sustained drop in prices.
But on Thursday Evans, whose views have been in step with those of Bernanke, said he believes the drop in inflation is temporary, and does not call for any immediate Fed policy response.