Hospitals often have limited ability to obtain primary clinical data from electronic health records to use in assessing quality and safety. We outline a new model that uses administrative data to gauge the safety of care at the hospital level. The model is based on a set of highly undesirable events (HUEs) defined using administrative data and can be customized to address the priorities and needs of different users. Patients with HUEs were identified using discharge abstracts from July 1, 2008 through June 30, 2010. Diagnoses were classified as HUEs based on the associated present-on-admission status. The 2-year study population comprised more than 6.5 million discharges from 161 hospitals. The proportion of hospitalizations including at least one HUE during the 24-month study period varied greatly among hospitals, with a mean of 7.74% (SD 2.3%) and a range of 13.32% (max, 15.31%; min, 1.99%). The whole-patient measure of safety provides a global measure to use in assessing hospitals with the patient's entire care experience in mind. As administrative and clinical datasets become more consistent, it becomes possible to use administrative data to compare the rates of HUEs across organizations and to identify opportunities for improvement.