title: Unwanted variations in the rules of practice.
authors.forename: J E
authors.initials: JE
authors.lastname: Wennberg
mesh_terms: D006801:Humans; D006278:Medicare; D010043:Outcome and Process Assessment, Health Care; D010817:Physician-Patient Relations; D010818:Practice Patterns, Physicians' / Q000592:standards*; D011366:Professional Review Organizations; D014481:United States