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 Healthcare 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. Copyright © 2006 by the American College of Medical Quality.