Health data come from many settings, including clinical care, insurance claims, registries, research, and public health. Each source organizes and codes information differently, so the same clinical idea may appear in many forms. The OMOP Common Data Model provides a shared structure for the data, and the OHDSI Standardized Vocabularies provide a shared way to represent clinical meaning.
Standardization does not make every database identical or eliminate differences in data provenance, capture, or quality. It transforms source data into a consistent research representation while retaining information about the original source. Researchers can then define an analysis once and apply the same specification across participating OMOP databases, while assessing whether each database is fit for the intended use.
OMOP can represent data originating from EHRs, claims, registries, and other healthcare sources. The EHDEN descriptive study illustrates this diversity: its 210 harmonized sources across 30 countries included primary care, secondary care, mixed-care, disease-specific, population-based, EHR, and laboratory data.
When participating organizations use the same data and vocabulary standards, researchers can define an analysis once and run it consistently at each participating site. Patient-level data remain under each data partner’s control. Approved aggregate results can then be brought together, while study definitions, code, and diagnostics remain transparent and comparable across settings.
