Agency for Healthcare Research and Quality (AHRQ) This is a U.S. federal agency under the Department of Health and Human Social Services that summarizes all the available data about the quality and effectiveness of treatments for specific conditions. Free. Website: www.ahrq.gov/clinic/epc/Phone: 301 427-1364Mailing Address:540 Gaither Road Suite 2000Rockville, MD 20850Date Updated: 4/16/2010