In this study, researchers used Delphi consensus methods to gather expert input to develop patient safety indicators (PSIs) for the perioperative setting. They developed 11 PSIs and tested them in 8 hospitals, which revealed wide variation in compliance. They propose a perioperative stops checklist and recommend a mortality and morbidity registry, which should be tested as possible clinical indicators on a larger scale to determine their validity and utility for measuring patient safety in this setting.