This large study used 9 years of national fee-for-service Medicare data to examine differences in surgical outcomes between hospitals participating in the National Surgical Quality Improvement Program (NSQIP) and nonparticipating hospitals. There was no statistically significant difference in the rate of improvement for any of the measured outcomes—risk-adjusted 30-day mortality, serious complications, reoperation, or 30-day readmissions—at 1, 2, or 3 years after enrollment in NSQIP versus well-matched controls. Notably, over 6 years there has been a trend toward reductions in mortality, serious complications, and readmissions across hospitals, regardless of NSQIP participation. The results of this study strengthen those of the study by Etzioni and colleagues in the same issue of the Journal of the American Medical Association. In an accompanying editorial, Dr. Donald Berwick states, "it is implausible to conclude that knowing results is not useful—perhaps essential—for systematic improvement of outcomes," but that hospitals must realize measurement alone is insufficient.