Proposed Vocabulary Tooling Requirements

Purpose

Health Level Seven currently maintains several tools focused on terminology management and distribution. HL7 has agreed in principle to align its vocabulary tooling with the IHTSDO, to enable interoperability with HL7 tooling and the IHTSDO Workbench. This document sets out the proposed requirements for HL7 vocabulary tooling. It comprises a detailed description of what HL7 vocabulary tooling must, should and may deliver that will be used to:

• Maintain HL7's vocabulary
• Distribute HL7's vocabulary to internal and external users
• Support review and analysis of HL7's vocabulary
• Develop value sets for HL7 standards
• Manage the distribution of HL7's vocabulary

Intended audience

The audience for this document includes HL7 Working Groups, project personnel, vocabulary facilitators and tooling implementers.

Conventions

For the purpose of this document, the terms vocabulary and terminology are to be considered equivalent.

HL7 Tooling Overview

A key piece in the development and deployment of the HL7 V3 Standard is the ability to bind structured vocabulary elements to HL7 V3 models. As such, HL7 has developed and maintains a robust structured vocabulary to facilitate the specialization or constraint of HL7 V3 models. The HL7 vocabulary - like all other structured vocabularies - requires a mechanism to facilitate efficient searching, validation and deployment its vocabulary

To this end, HL7 currently maintains several tools focused on the ability to search, maintain and publish its vocabulary. These tools are intended to support the terminology management and maintenance process defined by HL7 as the RIM and Vocabulary Harmonization processes. This combination of vocabulary maintenance processes along with supporting terminology maintenance tooling constitutes the solution to HL7’s terminology management solution. HL7’s current vocabulary tooling assets include:

• Design Repository

The Design Repository (distributed as a rimRepos ZIP file under the Design Repository project in Gforge) holds the reference specification for the HL7 RIM and vocabulary. For the purpose of vocabulary, the Design Repository MIF (Model Interchange Format) representation serves as the source of truth for the HL7 vocabulary.

• RoseTree

RoseTree is a Visual Basic application that provides a browser for the HL7 RIM and Vocabulary. RoseTree builds R-MIMs and HMDs from Visio designs and manages the repository storage of these artifacts, as well as generates XML extracts from the repository Publication Database (PubDb) for desktop and production publishing. RoseTree can process vocabulary content from either the MS Access or MIF representation formats from the Design Repository.

• Vocabulary Maintenance Language (VML) Maintenance Tools

The VML vocabulary maintenance environment is a combination of a structured XML schema that defines the allowable operations that can be performed on the HL7 vocabulary, as well as a set of Java APIs that takes files conforming to the VML schema definitions as input, and updates a MS Access repository that serves as the HL7 Vocabulary repository. The final step is for the vocabulary content represented in the relational MS Access model to be exported into HL7’s Model Interchange Format (MIF).

It is necessary for VML users to hand develop the VML files that serve as input to the Java environment. This has resulted in limited uptake for VML within the Harmonization community.

The VML maintenance environment was developed at Mayo Clinic as a temporary solution to HL7’s vocabulary maintenance needs. It has been recognized within the HL7 community that the current vocabulary tools are inadequate to meet HL7’s growing vocabulary maintenance needs. Several efforts have been undertaken to try to improve the vocabulary tooling infrastructure within HL7, however, due to the varying use cases and requirements across different terminology users, a unified total solution has not been completed.