ROME: REDCap Ontology Metadata Extension

This module provides support to annotate fields in REDCap with references to various ontologies. The aim is to make data Findable as described in FAIR data. This is different from using ontologies like ICD10 or SNOMED-CT to describe data, which is already supported by REDCap.

Features

• Ontology Annotations

  • Annotate fields with standardized concepts (e.g., SNOMED CT, LOINC)
  • Store structured metadata (CodeableConcept-like JSON)

• Configurable Ontology Sources

  • Allows uploading of minimal datasets (FHIR Questionnaire format)
  • Supports connection to BioPortal (any supported ontology)
  • Supports connection to Snowstorm (SNOMED CT server)

• Inline Authoring Experience

  • Annotate directly within REDCap's Online Designer
  • Minimal friction for end users

• Performance-Conscious

  • Caching strategies for remote terminology queries

• Structured Storage

  • Annotations are stored as JSON within field metadata
  • Designed to be both human-editable and machine-readable

Purpose

ROME adds a semantic layer to REDCap projects by enabling:

• Consistent definition of variables
• Reuse of standardized concepts
• Improved data clarity and comparability

How does it work?

This module provides a user interface (accessible at various places) that facilitates annotation of fields:

• The field itself, i.e., what it captures
• For categorical fields, what the choices represent
• For numerical fields, the unit

The full annotation is captures as a JSON structure in the @ONTOLOGY action tag inside the Field Annotation of a field.

Thus, annotations are integral parts of fields and consequently part of the data dictionary. The annotation format is described in detail here.

Installation

Automatic installation:

• Automatic installation will be available once a release is available and has been submitted to the External Module Repository.

Manual installation:

• Clone this repo into <redcap-root>/modules/rome_v<version-number>.
• Go to Control Center > Technical / Developer Tools > External Modules and enable 'ROME: REDCap Ontologies Made Easy'.

Configuration

After installation, the module's cache mechanism needs to be set up using the built-in external module configuration in Control Center. ROME will not work until this step has been completed.

Further configuration is done on the ROME: REDCap Ontology Metadata Extension plugin page. To be able to annotate fields, at least one ontology source has to be added to a project.

To add ontology sources to a project, go to the Manage tab and add:

• Local sources (such as an annotated FHIR Questionnaire)
• Remote sources (such as BioPortal or Snowstorm)
• System sources (these are local or remote sources set up by a REDCap admin to be available for use in projects)

Furthermore, project designers can choose to make annotations discoverable or not.

Admins can pre-configure local and remote sources for use by projects on the Global Configuration tab.

Additional admin options include:

• Enabling or disabling debug output to the browser console (should be off in production)
• Allowing or disallowing the use of the BioPortal token set up in REDCap (if available) for BioPortal ontology searches configured in projects
• Allowing access to the Global Configuration tab to users with design rights in certain projects (this allows delegating ROME administration to select users without the need for them to have access to the Control Center; these users won't be able to see or change the admin-only options)

Usage

Visit the ROME: REDCap Ontologies Made Easy plugin page to manage ontology annotations.

Learning about ROME

Check out the About tab.

Adding annotations

Annotation is done in the Online Designer's Edit Field dialog. In future versions, further annotation facilities may be added to the Annotate tab.

Searching an instance

Use the Discover tab on the plugin page in any project with the module enabled. Ontology codes can be selected and a list of projects that capture data matching these ontologies is displayed. Only projects that have opted in to be discoverable are included in the search.

Merging annotated data

Check out the Utilities tab. This content is still experimental. For now, an R function is provided to combine datasets from different REDCap projects that have been annotated using ROME.

How to cite this work

Meigen, C. and Rezniczek, G. A. (2026). ROME: REDCap Ontologies Made Easy (REDCap External Module) [Computer software]. https://doi.org/10.5281/zenodo.18525817

Or by adding this reference to your BibTeX database:

@software{Meigen_Rezniczek_ROME_REDCap_EM_2026,
author = {Meigen, Christof and Rezniczek, Günther A.},
doi = {10.5281/zenodo.18525817},
title = {{ROME: REDCap Ontologies Made Easy (REDCap External Module)}},
url = {https://github.com/REDCap-German-User-Group/ontology-annotation},
version = {1.0.0},
year = {2026}
}

These instructions are also available on GitHub under 'Cite This Repository'.

Support

This work was supported by TMF – Technologie- und Metho­den­plattform für die ver­netzte medi­zi­nische Forschung e.V. (project V141-01).