Initial enthusiasm for the role of checklists in reducing perioperative complications has been tempered by subsequent studies that did not replicate the safety improvements. This study evaluated the effect of the Keystone Surgery program, which combined an evidence-based checklist and the comprehensive unit-based safety program to enhance safety culture. Comparison of Keystone Surgery hospitals to those that did not implement the intervention found no differences in outcomes (including surgical site infections and 30-day mortality) between groups. The investigators acknowledge that many participating sites lacked the infrastructure to collect and regularly feed back performance data to frontline providers, which may have limited the effectiveness of the intervention. The study adds to a growing body of literature that emphasizes the role of effective implementation and monitoring in ensuring the success of checklist-based interventions. A PSNet interview and perspective explore the development and use of checklists to augment safety in health care.