['To test the hypothesis that surgeon volume would not predict short- and long-term outcomes when evaluated in the setting of technical credentialing.', 'Surgical volume is a known predictor of outcomes; the importance of technical credentialing has not been evaluated.', 'Fifty-three credentialed surgeons operated on 871 patients in the Clinical Outcomes of Surgical Therapy Study (NCT00002575), investigating laparoscopic versus open surgery for colon cancer. Credentialing required that each surgeon document performance of at least 20 laparoscopic colon cases and demonstrate oncologic techniques on a video-recorded case. Surgeons were separated based on volume entered into the trial (low, < or =5 cases (n = 39); medium, 6-10 cases (n = 9); or high, >10 cases (n = 5)) and compared by outcomes.', 'Patients treated by high volume compared with medium or low volume surgeons were older (70, 66, and 68 years; P < 0.001), more often had right-sided tumors (63%, 46%, and 53%; P < 0.001) and had more previous operations (48%, 38% and 45%; P < 0.004), respectively. Mean operative times were shorter (123, 147 and 145 minutes; P < 0.001), distal margins longer (13.4, 12.4 and 11.6 cm; P = 0.005), and lymph node harvest greater (14.8, 12.8, 12.6; P = 0.05) for high versus medium versus low volume surgeons. However, rates of conversion, complications, 5-year survival, and disease-free survival showed no significant differences.'] Does surgeon volume predict outcomes in the setting of technical credentialing : results from a randomized trial in colon cancer?