This study provides an evaluative framework for addressing whether our health care system is safer compared to years past. The authors discuss a measurement approach that focuses on the following: how often do we harm patients, how often do patients receive the appropriate interventions, how do we know we learned from defects, and how well have we created a culture of safety. Building on a model of structure, process, and outcome measures used to evaluate health care quality, the authors present a detailed discussion of attributes necessary for safety-specific measures. They provide a case-type example of their suggested process to illustrate their framework. Reflecting on the 5 years since release of the IOM report, past commentaries by Leape and Berwick as well as Wachter focused on progress in patient safety and provide further context to the efforts of this study.