John Williams, research director at the Federal Reserve Bank of San Francisco, said that while monetary policy is likely to remain accommodative for some time, policy makers will reverse course at the appropriate time.

“I want to emphasize that, when the right time comes, the Fed will reduce monetary stimulus,” Williams said in the text of a speech in San Francisco.

Williams reiterated the Federal Open Market Committee’s pledge to keep an accommodative policy in place for an “extended period,” saying that it will take “quite some time” before unemployment falls to a level that pushes inflation too high based on the San Francisco Fed’s forecasts. He added that “even the best forecasts can be wrong.”

“A great deal of thought has gone into designing the proper ways to unwind the measures now in place,” Williams said in a speech to the Chicago Booth Graduate School of Business Alumni Club of San Francisco. “I’m confident we’ll be able to do so successfully and maintain price stability.”

The San Francisco Fed has been without a president since last year, when Janet Yellen joined the Fed board in Washington as its vice chairman. Williams has given speeches on behalf of the San Francisco Fed while the search for Yellen’s successor is under way.