The use of electronic health records (EHR) in US medical facilities has increased rapidly over recent years. Incorporating EHRs has facilitated clinical practice, resulting in widespread access to patient information and potentially better care. Beyond their primary use for direct clinical care and billing, EHRs provide a valuable source of data for “secondary uses,” including research, quality measures, disease surveillance, and administrative applications. Because of the quantity of data in the EHR of a typical healthcare system, secondary use of this data can be of enormous benefit.