Progress in improving patient safety has been hampered by a lack of standardized outcome measurements that are sufficiently rigorous for comparing safety between hospitals. This report from the National Quality Forum endorses six evidence-based measures that are suitable for public reporting and quality improvement efforts. The measures—relevant to specific types of health care–associated infections (including central line–associated bloodstream infections) and radiation exposure from diagnostic imaging—were endorsed after a rigorous evaluation process that, interestingly, found that measures of other well-documented safety problems (such as medication errors) were not reliable enough to be used for comparison across institutions.