New York

FEDERAL Reserve officials, who are expected to raise interest rates next month, are already sketching out positions for a post-liftoff debate that may blur the lines between inflation "hawks" and "doves" and make the Fed's policy less predictable.

With unemployment steadily falling, Fed policymakers have been waiting for a return of healthy price and wage increases. But those have yet to appear, prompting some within the central bank to begin doubting whether their tried and tested economic models still work.