We thank O’Sullivan et al for their comments. They raise 2 important questions. The first is what might be the cause of day-after performance decrements associated with excessive alcohol consumption, and the second is what to do about it. Like O’Sullivan et al, we believe that the observations made in both studies are robust.1 The reason that similar observations have not been made before probably has to do with the assessment capabilities available to researchers. As pointed out by O’Sullivan et al, the Minimally Invasive Surgical Trainer Virtual Reality (MIST-VR) simulator is one of the most rigorously validated virtual reality simulators, as both an assessment and training device.2- 4 This ability to precisely measure psychomotor surgical performance affords us the opportunity to draw clear and statistically powerful conclusions from studies with relatively small numbers of participants. The lack of this measurement capability has probably limited the strength of conclusions from similar studies in other skill domains.5- 6 Acceptance of the performance decrement, as demonstrated by the methodology used in the studies reported,1 can serve as a starting point for investigations into the exact mechanisms of performance degradation. These studies could also help us to define what “excessive” means. In turn, this may help us to determine what levels of alcohol consumption might be acceptable the night before operating. On the one hand, an alcohol ban the night before operating that is based on current data may be overly zealous (at this time). However, microvascular surgeons, neurosurgeons, and ophthalmic surgeons are all too aware of how easy it is to compromise technical performance (eg, hand tremor) with factors as benign as caffeine consumption, dehydration, and fatigue.7 Furthermore, we believe that the performance decrements observed in both studies1 may have been attenuated because the tasks were image-guided and laparoscopic, thus imposing considerable sensory, perceptual, cognitive, and psychomotor difficulties on the subjects (precisely the same conditions under which endoscopic surgeons must operate daily). It is also probable that these effects would be further attenuated for fluoroscopic or ultrasound-guided procedures in which operators must work under conditions of even greater information degradation. Issues highlighted and quantified by surgery would once again appear to raise important questions for procedural performance in other specialties.