title: Preface to the AHRQ supplement.
authors.affiliation: Agency for Healthcare Research and Quality, John M. Eisenberg Building, 540 Gaither Road, Rockville, MD, 20850, USA, Scott.Smith@ahrq.hhs.gov.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Smith
mesh_terms: D006801:Humans; D017063:Outcome Assessment, Health Care; D035583:Rare Diseases; D012109:Research Support as Topic; D014481:United States; D016270:United States Agency for Healthcare Research and Quality