1. Division of Otolaryngology, Wisconsin Surgical Outcomes Research Group, Department of Surgery, University of Wisconsin, Madison
2. Division of Thyroid and Parathyroid Endocrine Surgery, Massachusetts Eye and Ear Infirmary, Boston3Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts
3. The VA Outcomes Group, Department of Veterans Affairs Medical Center, White River Junction, Vermont5Section of Otolaryngology in Geisel School of Medicine at Dartmouth, White River Junction, Vermont6The Dartmouth Institute for Health Policy & Clinical Practice, Lebanon, New Hampshire