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Enterprise Vocabulary Services (EVS) works with NCI and extramural partners to develop, license, and publish terminology; to support software applications; and to promote harmonization and shared standards. EVS provides the foundational layer for NCI's informatics infrastructure, and participates in federal and international standards efforts.

Below you will find short descriptions of our resources and links to their online browsable locations. If you wish instead to download vocabulary or software distributions please visit our EVS Downloads page. For additional details on EVS resources, applications, and services, please visit the EVS Wiki.

EVS Terminology

EVS has collected, created, and cross-mapped these biomedical terminology resources:

NCI Thesaurus (NCIt)

NCIt is NCI's reference terminology and core biomedical ontology. It covers approximately 100,000 key biomedical concepts with terms, codes, definitions, and more than 200,000 inter-concept relationships. It is a shared resource: nearly half of NCIt concepts include content tagged by one or more EVS partners.

NCI Metathesaurus (NCIm)

NCIm provides a concept-based mapping of terms from more than 70 biomedical terminologies, whose 3,600,000 terms are mapped to 1,400,000 concepts representing their shared meanings. NCIm also provides a reference resource for users seeking definitions, synonyms, codes, and other information.

Other Terminologies

These terminologies are available through the NCI Term Browser:


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Terminology Mappings

EVS has published pairwise mappings between several supported terminologies to support data translation and cross-referencing. These mappings generally reflect EVS community interests and collaborations.

Terminology Value Sets and Data Standards

EVS maintains hundreds of NCIt subsets and other code lists. Most are available as CTS 2 value sets following the draft Common Terminology Services Release 2 (CTS 2) specification. In caDSR, such value sets provide a pre-curated, standard set of meanings for use by metadata curators.

Key EVS-supported terminology standards include

FDA Terminology

EVS works with the U.S. Food and Drug Administration (FDA) to develop and support controlled terminology in several areas. More than 10,000 FDA terms and codes are stored in NCIt.

Federal Medication Terminology

EVS is a partner in the Federal Medication (FedMed) collaboration, which is developing shared FedMed Terminology (FMT) and standards to improve the exchange and public availability of medication information.

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CDISC Terminology

The Clinical Data Interchange Standards Consortium (CDISC) — an international non-profit organization that develops and supports global data standards for medical research — has chosen EVS as one of its terminology partners.

NCPDP Terminology

The National Council for Prescription Drug Programs (NCPDP) creates and promotes the transfer of data related to medications, supplies, and services through the development of standards and industry guidance.

NICHD Terminology

The National Institute of Child Health and Human Development (NICHD) works with EVS on the Pediatric Terminology Harmonization Initiative, providing standardized coding for pediatric clinical trials and other research activities.

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EVS Applications

EVS manages a wide variety of terminology content, which is produced, exchanged, and processed through many different formats, data structures, and interfaces. This requires a variety of specialized terminology tools and systems able to handle complex data and apply logical-inference operations, business rules, and other processing routines. Where possible, EVS works with other partners to develop shared open-source terminology applications.

Key EVS terminology tools include


This is the EVS terminology server. It comprises a collection of software and services for loading, publishing, and providing access to vocabulary and ontology resources. The Mayo Clinic developed LexEVS as an open-source tool with NCI support. Many NCI and external applications, including the cancer Data Standards Registry and Repository (caDSR), use the server's application programming interfaces (APIs).

EVS Terminology Browsers

The NCI Term Browser and the NCI Metathesaurus Browser are cross-linked terminology browsers designed to meet NCI's information needs across the full range of EVS content. The browsers are available as open-source software, use LexEVS servers, and have been adopted by others who use LexEVS.

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NCI Protégé

This is the primary EVS editing software application. It is based on Stanford's open-source Protégé tool. NCI developed Protégé plug-ins to meet EVS requirements and business rules, then contributed the code back to the community to foster further Protégé adoption.

Other Applications

Several applications are used primarily for internal EVS terminology development and provide for community involvement as well. The source code for these applications is available for community contributions and re-use. For more information, contact CBIIT and NCIP Application Support.

EVS Term Suggestion
This software is used — either standalone or integrated into the EVS terminology browsers — to collect community feedback and contributions for both NCI and EVS partner terminology products.

EVS Report Writer
This is a standalone software application that connects to the LexEVS servers. It supports NCI work as well as that of external partners.

EVS Value-Set Editor
This application is used to create and maintain CTS 2 value-set and pick-list definitions for loading into the LexEVS server, which resolves the definitions against referenced terminologies.

EVS Mapping Tool
This application supports mapping between term lists, value sets, terminology subsets, or whole terminologies. It provides a mix of automated and manual methods for creating, editing, and publishing mappings; connecting to LexEVS for terminology content; and producing XML mapping data files.

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