The authors conducted a study to investigate the variability of measurement of the proximal articular set angle. The proximal articular set angle as measured radiographically was compared with the proximal articular set angle as measured intraoperatively. Three groups of evaluators--attending physicians, residents, and third-year podiatric medical students--measured the proximal articular set angle radiographically. The mean measurement, standard deviation, and difference between the mean radiographic measurement and the intraoperative measurement were determined for each group. The authors concluded that the only accurate proximal articular set angle measurement is the intraoperative measurement.