This disclosure describes systems, devices, and techniques for automatically identifying missing or ambiguous information in documentation associated with a patient. For example, a system may include one or more computing devices configured to receive documentation comprising a plurality of documented items related to the patient and determine, based on at least a subset of the plurality of documented items, one or more undocumented items missing from the documentation, wherein the subset of the plurality of documented items and at least one of the one or more undocumented items define a medical concept. The one or more computing devices may also be configured to generate, based on the one or more undocumented items, a code representative of the one or more undocumented items and output the code.