1. Department of Otolaryngology-Head and Neck Surgery; Northwestern University Feinberg School of Medicine; Chicago IL
2. Department of Otolaryngology-Head and Neck Surgery; Hospital of the University of Pennsylvania; Philadelphia PA
3. School of Medicine and Dentistry; University of Rochester School of Medicine; Rochester NY
4. Department of Otolaryngology; Vanderbilt Bill Wilkerson Center; Nashville TN
5. Division of Allergy-Immunology; Department of Medicine, Northwestern University Feinberg School of Medicine; Chicago IL
6. Center for Health Research; Geisinger Health System; Danville PA
7. Center for Healthcare Studies; Northwestern University Feinberg School of Medicine; Chicago IL