Checklists for basic procedural skills require an approach to standard setting in which patient safety concerns are paramount. We suggest that faculty members identify dimensions such as patient or clinician safety, procedure outcome, and patient comfort that are essential for a given procedure and demand for essential checklist items a high level of mastery that is not compensated by performance of nonessential items. This approach differs from traditional standard setting methods developed for written examinations, which allow examinees to miss a given percentage of items regardless of the specific items missed. Application of cut scores based on this patient safety standard resulted in requiring a substantial number of students to retrain and retest; these students would have passed if the traditional Angoff method had been used. Only by demanding a high level of mastery in the simulation laboratory can we promote patient safety in the messy and unpredictable real world.