This page provides an overview of the THEMIS project.


OHDSI Community: Themis makes decisions for the good of the whole community. We must compromise. We can always revisit and modify the convention. Don’t let perfect be the enemy of great. And interoperability between different OMOP CDMs is great!

What falls under Themis and what does not

Some questions regarding the CDM would fall under the CDM WG domain, Vocab Team’s domain, and/or other areas of the OHDSI community.

  • CDM WG: Model changes

  • Vocab Team: A missing Vocabulary, concept_id, or vocabulary representation

  • Themis: Lack of a convention

    • Multiple places to store or represent a data element
    • Required data element not present at the source (example: year of birth)
    • Multiple data points for a field containing a single data element (example: multiple provider specialties)
    • General questions about how, where, when, why to store a data element
    • Make recommendations to CDM & Vocab WGs

Topic Processing

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  1. Anyone in the OHDSI community can propose an idea for change, with or without a solution. This person is the issue sponsor. To do that, go to the THEMIS GitHub and use the issue template to add the necessary details.
  2. The issue will be posted to the OHDSI forum for input and debate for a period not less than 60 days. During this time, the issue sponsor should edit the issue based on community feedback to ensure the proposed solution is inclusive of differing data sources and use cases.
  3. Themis will add this issue to the agenda.
  4. The sponsor will present the proposed convention discussion during a Themis meeting. The proposed solution along with the forum discussion will be reviewed by the Themis WG. Objective of meeting: To ensure the majority of the Themis community agrees with the proposed decision and the documentation and wording of documentation is clear and concise and provides unambiguous guidance on how to handle these data.

There are 3 possible outcomes after the Themis WG review of the issue and proposed solution.

  1. The recommendation is accepted, with or without modification, and the convention is ratified. Themis will document the convention and metadata using the Themis metadata template for ratified conventions.
  2. If the recommendation is rejected, the issue will be labeled as such with notes of why it was rejected and the issue will be closed.
  3. The convention requires more context, documentation or other details. It will be sent back to requestor for modification.

Getting Involved

Tags: themis