Example of a semantic mapping of self-reported hypertension. Mapping is realized in 2 steps using: (1) UK Biobank vocabulary and (2) custom created nonstandard to standard concept mapping tables. OMOP: Observational Medical Outcomes Partnership; CDM: Common Data Model. Here, the UK Biobank data field 20002 (noncancer illness code, self-reported) with value 1065 (hypertension) is transformed to an OMOP an observation record with observation_concept_id 4214956 (History of clinical finding in subject) and value_as_concept_id 316866 (Hypertensive disorder).