How safe is your hospital? The Fall 2015 Hospital Safety Score rankings used 28 measures to determine a grade for hospitals that represents its overall performance in keeping patients safe from preventable harm and medical errors. As many as 440,000 people a year die each year from hospital errors, injuries, accidents and infections, according to The Leapfrog Group, which pulled data from the Agency for Healthcare Research and Quality (AHRQ), the Centers for Disease Control and Prevention (CDC), the Centers for Medicare and Medicaid Services (CMS), and the American Hospital Association's Annual Survey and Health Information Technology Supplement.