Data on a total of 1485 patients with OPSCC were gathered from the 6 institutions. After reviewing the clinical data and WSI image quality, 391 of the patients were excluded. A total of 1094 specimens remained for the analysis. SCPMG, Southern California Permanente Medical Group; WUSTL, Washington University in St. Louis; JHU, Johns Hopkins University; MEDVAMC, Michael E. DeBakey VA Medical Center; CCF, Cleveland Clinic Foundation; VUMC, Vanderbilt University Medical Center.