There is no established method for defining when a surgeon reaches the proficiency plateau in performing a specific operation. The published literature refers to "learning curves" based on retrospective evaluation of operative time, conversion rates, morbidity etc., which lack objectivity and do not address individual human factors. A more useful study of the gain in proficiency by the individual surgeon for a particular operation may be obtained using observational clinical-human reliability assessment (OCHRA).Following an 8-month fellowship in advanced laparoscopic surgery, the surgeon M.T. performed, independently at his own hospital, a prospective series of 20 palliative bypass operations for advanced gastric or pancreatic cancer. Unedi...