Ensuring the quality of SNOMED CT

  1. Managing the stability of SNOMED CT content, so that SNOMED-encoded data retains its meaning over time.
  2. Maintaining the integrity of clinical knowledge in SNOMED CT for the priority use cases: Semantic interoperability, aggregated reporting and clinical decision support.
  3. Assuring the quality of the distribution files, to enable implementers to transition smoothly from one release to the next.

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Quality through expert personnel

SNOMED International employs experienced authors, who have clinical backgrounds in a broad range of clinical domains.

To add diversity of experience to the authoring team, SNOMED International contracts external consultant terminologists. SNOMED International currently has a Head of Terminology, nine authors and four terminology mappers, who in addition to mapping, undertake some authoring duties.

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Quality through guidance and training

Balancing current realities and anticipating future needs.

SNOMED International is committed to developing knowledge of SNOMED CT and authors' expertise with a suite of resources and training curricula including:


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Quality through process

Content development projects are managed from requests through publication using the content development process.

This process has been developed based on the Open Unified Process used in software development, and is applied to all content projects irrespective of size. The process standardizes methods for reviewing content changes, to ensure that problems are understood, solutions meet stated goals and are tested, and that content changes are correctly applied.

View the full process

Peer review workflow

The peer review process ensures that all content changes are reviewed by two authors. It also ensures that authors who change SNOMED content, and reviewers of those changes, agree that the changes are correct. Disputes are resolved during the authoring process, and may be escalated to the Head of Terminology for resolution. Authors who participate in peer reviews are members of the SNOMED International team.

Distribution file validation

Release files are subject to testing using an automated testing framework. The technical integrity of the release is tested, including the internal integrity of the distribution files. The framework also tests assertions about the content contained in the files.

View the full testing framework API

External review workflow

For some projects, domain experts who are external to SNOMED International agree to review content that is authored internally. The external review process applies to projects where SNOMED International requires additional domain expertise in the internal team, or where SNOMED International wishes to increase the capacity of the internal team.

Beta release process

SNOMED International Members are invited to subject prospective semi-annual releases to their own testing processes, during the two-week Beta release phase of the SNOMED CT release process. During the Beta release SNOMED International Members provide SNOMED International with feedback on the prospective distribution files. Where errors are identified, they are evaluated, and where possible they are corrected immediately.

Requestor-author feedback loop

All requests for change are handled through the Content Request Service (https://request.ihtsdotools.org), which provides requesters with up-to-date information on their requests. The tool also enables clarification to take place between the author and requester. In addition the requester obtains feedback on authored content, and is notified of the publication date.

Critical incident process

SNOMED International has developed a critical incident process to ensure that where defects are discovered in SNOMED CT, they are evaluated and quickly corrected.