The BRIDG Harmonization Process

The Technical Harmonization Committee (THC)

The process of moving content into the BRIDG model is executed by the Technical Harmonization Committee (THC).  Members of the THC all have clinical trial experience, standards building experience, and modeling experience.  Working under direction from the BAB, the THC has monthly meetings to consider harmonization artifacts from various project teams for inclusion in the BRIDG model.  A “harmonizable artifact” is a documented representation of a particular aspect of the semantics of the domain-of-interest to the presenting project team.  Harmonizable static artifacts include fully documented class diagrams (and instance diagrams as necessary), whereas harmonizable dynamic artifacts include fully documented activity diagrams with swim lanes, state diagrams, and/or sequence diagrams.  Experience has shown the wisdom of the THC having two or three “reality checks” with a given project team over the lifecycle of the project and prior to the team’s formal submission of its artifacts to the THC to ensure that the project team is creating analysis level artifacts suitable for BRIDG harmonization, as well as to ensure that they are applying good UML modeling and documentation practices to their analysis model artifacts (since these artifacts, by and large, are constitute the BRIDG Harmonization Artifact Submission Set for the team).  A discussion of the processes involved in utilizing the BRIDG model in the context of the caBIG™ CTMS WS can be found in Section 1.x.

The THC meets monthly for a three-day session.  Between meetings, conference calls and email exchanges are conducted as needed.  Based on harmonization priorities established by the BAB, the face-to-face meetings consist of working with representatives from the scheduled project team to fold the new content into the existing BRIDG model.  The project team is required to bring to the THC session a BRIDG Mapping Document (discussed in more detail in Section 3.x) which identifies specific representation choices of semantically equivalent structures between the submitting team and the existing BRIDG model.  The Mapping Document is used as a working reference during the THC meeting to facilitate BRIDG representational choices which may, of course, involve changes to the existing BRIDG model as new concepts are including, existing concepts are disambiguated based on the submitting team’s additional perspectives, etc..  Beginning with the new release schedule post R 1.0, the THC plans to have eight harmonization meetings each year, reserving every third month’s meeting for preparation for the next release (i.e. addressing of comments, updating of release artifacts, etc.

The size of the THC has been kept small, since the THC is more effective as a small group focused on making representation rather than semantic content decisions, i.e. the THC assumes that the larger community has participated in vetting the various harmonizable artifacts that are presented to the THC and/or that the community will respond to the various published versions of the BRIDG model with appropriate feedback which will, in turn, drive the content of future BRIDG releases.  The BRIDG model only succeeds if the community interested in its semantics utilizes it as a DAM and informs the THC of its errors of omission and commission, errors which the THC is committed to promptly addressing in future releases.

Likewise, the CDISC BoD formally committed to reverse engineering all of its existing specifications (e.g., ODM, SDTM) into the BRIDG Model in addition to committing to using the BRIDG model as a part of future CDISC specification projects.  Finally, the Clinical Trial Management System Work Space (CTMS WS) of the caBIG™ project announced that all applications built under NCI funding for use in the CTMS WS must utilize the BRIDG model as the starting point for application analysis activities and requirements specification and, as part of the final application deployment process, harmonize their application semantics with the BRIDG model so that interoperability in the CTMS WS will be based on exposed BRIDG Application Program Interfaces (APIs).  Each of these efforts had the effect of expanding both the profile and the specific semantics in the BRIDG model.  However, it should be noted that the definition/boundary of the BRIDG model has not been required to be expanded beyond its original statement: Protocol-driven research involving the assessment of  the utility, impact, or other pharmacological, physiological, or psychological effects of a drug, procedure, process, or device on a human, animal, or other biologic subject or substance plus all associated regulatory artifacts.  

(NOTE:  The current semantics of the BRIDG model are scoped to human subjects, i.e. the semantics do not support pre-clinical trials on animals or other non-human biologic entities.  Future releases of the BRIDG model are expected to include semantics for non-human subjects as that content is brought forward for harmonization.  It is expected that the inclusion of the additional semantics would, for the most part, involve the addition of new Green, Yellow, and Turquoise classes rather than new Red classes. 

Steve Bridge

University Researcher at On Leave
I'm a researcher specialising in microbiological data analysis, including the natural ecosystem influences and changes over time.