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Unified Medical Language System® (UMLS®)

UMLS Source Inclusion Evaluation Criteria and Background Questions

Version 1.0 - September 20, 2018

To consider a new source vocabulary for inclusion into the Unified Medical Language System (UMLS), the National Library of Medicine (NLM) needs to understand details about your vocabulary and why you would like NLM to add your vocabulary to the UMLS. Answering the questions below will provide NLM with a better understanding of your vocabulary and if it meets the criteria for inclusion. Please provide as much information as possible to assist NLM in making an informed decision regarding the inclusion of your vocabulary into the UMLS. NLM reserves the right to change these questions and criteria at any time.

You can download an editable version of the questions below and then submit the completed document to NLM Customer Support.

Source Vocabulary Name:
Vocabulary Point of Contact:
Brief Vocabulary Description:

Inclusion Evaluation Criteria

Value to UMLS

NLM wants to understand the use cases for your vocabulary and its user communities.

  • What are the use cases for your vocabulary?
    • Which user communities will the vocabulary serve?
  • How will adding your vocabulary to the UMLS contribute to interoperability among the currently available electronic resources?
    • For example, will the addition of your vocabulary help link currently available electronic resources, such as patient records, journals, texts, etc.?
  • Is there significant overlap between your vocabulary and other UMLS source vocabularies?
    • Will your vocabulary bring new or unique content to the UMLS?

Source Vocabulary Content

NLM wants to understand your vocabulary content, including the organizational principles and editorial guidelines used to create your vocabulary.

  • Are thesaurus characteristics and principles used to create your vocabulary?
    • Is it concept-oriented (i.e., organized by meaning)?
    • Are there preferred terms or synonyms?
    • Do you have codes/identifiers associated with names?
    • Is there a principled hierarchy?
    • Do explicitly defined relationships exist between the terms, such as broader than/narrower than relationships?
    • Are there definitions or other associated information?
    • Are there mappings or connections to other vocabularies?
  • Are the meanings of your terms clearly distinct when seen alone, rather than in the associated context?
    • Will there be many cases where the ‘face’ meaning of a term is different from the meaning of the same term in other areas of biomedicine?
  • Do you follow other source vocabularies’ content?
  • What parts of your vocabulary would NLM be permitted to publish in the UMLS?

Technical Process and Development

NLM wants to understand the technical aspects of your vocabulary.

  • Is the vocabulary available in a well-structured, computable electronic format?
    (NLM cannot accept printed publications, nor convert them.)
    • What is the format?
    • What is the data size of your vocabulary?
    • How many terms are in your vocabulary?
    • Is a sample set of files and documentation available?
    • Is there a technical contact person for questions about the files?
  • Will you provide your vocabulary data files to NLM free of charge?
    • If yes, how will you provide your data files to NLM?
    • Will there be an automated download capability?

Background Questions

NLM wants to understand additional details about your vocabulary.

  • Is your vocabulary actively maintained?
    (The UMLS will only accept source vocabularies that are actively maintained.)
    • What type of ongoing support does your vocabulary receive to ensure that it will remain a viable asset to the UMLS?
    • Is your vocabulary and its updates officially sponsored?
    • If so, please describe by whom and how they would be sponsored?
  • How often do you update your vocabulary content?
    • What is your update model?
  • Who is the responsible party or parties for your vocabulary?
    • Who is the vocabulary author?
    • Who creates your vocabulary?
    • Who owns the vocabulary?
  • Do you have a mechanism to maintain the integrity of your vocabulary?
    • How do you maintain the integrity of your vocabulary?
  • Is there a point of contact if there are content related questions?
  • Is there a mechanism in place to provide timely feedback or resolution to content-related questions?
  • Do you have an online browsing resource that NLM editors can use to access your vocabulary data or additional data about the information in your vocabulary?

Terms of Agreement

Source vocabularies included in the UMLS follow the terms of the UMLS Metathesaurus License Agreement. Please examine the UMLS Metathesaurus License Agreement and resolve any questions about copyright ownership. Source vocabularies must accept the UMLS Metathesaurus License Agreement in order to be included in the UMLS.

  • According to Appendix 1 and section 12 of the UMLS Metathesaurus License Agreement (and outlined on the License Category Help page), what have you determined your license restriction level to be (0, 1, 2, 3, or 4)?
  • Would you allow a subset of your vocabulary data to be published in the UMLS at a lower restriction level?
  • Would you allow your vocabulary to be exposed to users through open web interfaces and tools and/or open downloads and APls without user authentication?