Central banking practice adapts over time as markets evolve, Federal Reserve Vice Chairman Roger Ferguson said in notes prepared for a speech on Wednesday, adding that this had been Fed experience and would likely be shared by the ECB. In the text of a speech that made no reference to current economic conditions or monetary policy, Ferguson said that one of the Fed's most important tasks -- communicating with markets -- was a "work in progress." "Monetary policy arrangements do, and should, adjust over time to changes in the economic and financial environment," he said. The speech was prepared for an event hosted by the European Central Bank to mark the retirement at the end next month of ECB executive board member Tommaso Padoa-Schioppa. Ferguson was speaking ahead of the next meeting of the Federal Open Market Committee in Washington on May 3, at which the U.S. central bank is expected to raise interest rates by a quarter percentage point to 3.0 percent. Ferguson acknowledged that communicating with financial markets was an important tool used by the Fed. "Shaping the expectations of market participants can on occasion be an important adjunct to monetary policy," he said.