The purpose of this study is to demonstrate that caution should be exercised when using administrative data, exclusively, to report quality and safety outcomes. Investigators identified hospital-acquired decubitus ulcers using Agency for Health-care Research and Quality (AHRQ) patient safety indicator definitions. As validation of this method, investigators abstracted 123 medical charts of patients identified through AHRQ methodology as having hospital-acquired decubitus ulcers. Abstraction of these cases produced a change in rate from 23.3 decubitus ulcers per 1000 patients, derived through administrative data, to a true rate of 7.9 decubitus ulcers per 1000 patients, a 66% reduction. Investigators found 2 additional flaws (1 internal and 1 methodological) that further decreased the decubitus ulcer rate to 6.14 per 1000, a 74% variance. The results of this study suggest that administrative data, when used alone, are not sufficient in measuring the true rate of hospital-acquired decubitus ulcers.