[1] Univ Wisconsin, Dept Surg, Sch Med & Publ Hlth, Div Endocrine Surg, 600 Highland Ave,CSC K4-738, Madison, WI 53792 USA
[2] Univ Wisconsin, Dept Surg, Sch Med & Publ Hlth, Wisconsin Surg Outcomes Res Program, Madison, WI USA
[3] Med Coll Wisconsin, Wauwatosa, WI USA
[4] Drexel Univ, Dept Sociol, Philadelphia, PA 19104 USA
[5] Qualitat Hlth Res Consultants LLC, Madison, WI USA
[6] Univ Wisconsin, Dept Surg, Sch Med & Publ Hlth, Div Otolaryngol Head & Neck Surg, Madison, WI USA