Once electronic health records and other clinical systems used in patient care are digital, the focus turns to how this health information can be represented and shared using standards. Developing standards that are both sufficiently comprehensive and also implementable in practice is one of the long-standing health informatics challenges in part because of the complexity of the human body and the resultant complexity of patient care. We discuss data and data sharing (interoperability) standards separately but they are inevitably intertwined since the information being shared using interoperability standards is often represented using data standards.