This analysis of patient safety in Medicare patients from 2004-2006 concludes that while modest improvements have been made, patient safety incidents still account for more than 200,000 preventable deaths and nearly $9 billion in excess costs yearly. The report identifies "Distinguished Hospitals for Patient Safety"—the hospitals scoring in the top 15% according to a ranking methodology developed by the authors. As with prior HealthGrades reports, the study uses the Agency for Healthcare and Research Quality (AHRQ) Patient Safety Indicators (PSIs) to measure the incidence of patient safety problems and compare hospitals. The limitations of using PSIs as a performance measure have been discussed in a prior study and AHRQ WebM&M commentary, and it is important to note that this report did not undergo external peer review.