Federal Reserve Chairman Ben Bernanke will tell members of Congress on Wednesday morning that the central bank is planning to slow down its stimulus program later this year only if the economy continues to improve.

“I emphasize that, because our asset purchases depend on economic and financial developments, they are by no means on a preset course,” Bernanke cautions in remarks prepared for his semi-annual appearance before the House Financial Services Committee.

Bernanke said that the Fed’s plans are to taper its monthly bond purchases from the current $85 billion later this year and to end them altogether in mid-2015 to coincide with the unemployment rate falling to 7 percent, as forecast by the Fed. The unemployment rate right now is 7.6 percent. Bernanke also reasserted that the Fed would keep interest rates near zero at least until unemployment falls below 6.5 percent.

Bernanke’s dovish message and timeline for the planned tapering of monetary stimulus were not different than the ones that he initially sketched out at a June 19 press conference that rattled markets and sent Treasury bond and mortgage on a steep rise.

In the intervening time, however, events have cast some doubt on the Fed’s intentions. A number of Fed officials have made it clear in speeches and interviews that the market reaction to the introduction of a more detailed timeline was greater than they anticipated or intended. The recently released minutes of the Fed’s two-day monetary-policy meeting that culminated in Bernanke’s press conference, on the other hand, showed more debate among members of the Fed than Bernanke has let on.

On Tuesday, Kansas City Fed President Esther George said in a speech that the thresholds Bernanke outlined for reducing the size of bond purchases and then raising interest rates — 7-percent and 6.5-percent unemployment rates, respectively — should be triggers instead, leading to immediate changes in Fed policy. George is a voting member of the Fed’s monetary policy committee and dissented from the group’s most recent policy statement on the grounds that continuing large-scale asset purchases could raise inflation expectations. Philadelphia Fed President Charles Plosser made similar remarks about thresholds versus triggers for Fed reactions on Friday.

The tensions among Fed officials may be causing confusion among investors and traders about the Fed’s exact plans and guidance about monetary accommodation. Or as Roberto Perli, a former Fed economist, told the Wall Street Journal on Wednesday, “It’s not that the market does not understand the Fed’s message,” he said. “The problem is they’re kind of skeptical about it.”

Bernanke will answer questions from U.S. representatives at the hearing scheduled for Wednesday morning. He also will appear before the Senate Banking Committee on Thursday morning. The Federal Reserve chairman is required to report to both committees twice a year.