The Federal Reserve should be “quite patient” in removing stimulus despite falling unemployment because broader measures of the U.S. labor market remain weak, a top U.S. central banker said on Thursday. […] Rosengren’s remarks, prepared for delivery at the New College of Florida, in Sarasota, could shed light on what more esoteric measures of the labor market policymakers will analyze as the unemployment rate, which stood at 6.7 percent in December, drops toward the 6.5 percent threshold that the Fed has highlighted for raising rates.