This report reveals that the overall quality of care delivered by US hospitals improved steadily between 2003 and 2005, as measured by adherence to evidence-based treatments for myocardial infarction, congestive heart failure, and pneumonia. Adherence to the Joint Commission's National Patient Safety Goals, which include measures to prevent wrong-site surgery and promote medication reconciliation, was also measured. Although results on these measures showed a more mixed picture, the report cautions that changes in measurement during the study period limit interpretability of the results.