CDISC Conformance Rules are an integral part of the Foundational Standards and serve as the specific guidance to Industry for the correct implementation of the Standards in clinical studies.  An emerging Industry best practice is to use Conformance Rules on an ongoing basis, throughout the study, to keep the data as close to submission ready as possible and to ensure quality in all data exchange scenarios.

Current CDISC Conformance Rules need to be expressed in a common specification to be loaded to the CDISC Library. In addition, an executable component must be developed for every Conformance Rule.

Project Goals and Objectives

The overall goal of the CORE Project is to deliver a governed set of unambiguous and executable Conformance Rules for each Foundational Standard, and to provide a minimum viable product of an open-source execution engine for the executable Rules.

CDISC is partnering with Microsoft to develop the CDISC Open Rules Engine (CORE), open-source software, which will execute machine-readable CDISC Conformance Rules retrieved from the CDISC Library. The global clinical research community will be able to leverage the free and open, Microsoft Azure-based CORE software to test study data for conformance to CDISC standards as well as to regulatory and sponsor-specific conformance rule sets.

The CORE Project objectives are to:

  • Ensure each standard has a set of unambiguous, executable Conformance Rules
  • Ensure consistency across Conformance Rule implementations
  • Expedite the availability of executable Conformance Rules for new Foundational Standards
  • Create executable Conformance Rules vetted by the CDISC standards development teams
  • Release the Rules under the CDISC Open Source Alliance (COSA)
  • Create an open-source engine that executes the Rules

Further Considerations

  • The executable rules are the next step in the evolution of the Conformance Rules that CDISC publishes with every standard
  • Executable Conformance Rules available via CORE should make it much easier for rule vendors to adapt these rules for use in their software
  • CORE will be released as open source under the MIT license; it will not be offered by CDISC as a commercial product or service
  • Existing rule vendors are free to contribute to, or use, the CORE software

Project Concept Diagram

The following diagram illustrates the concept of the CORE project, including the Conformance Rules, the executable form of the Rules, and the Rules’ execution engine:



  • CDISC will collaborate with Industry to develop a specification of the Rules.
  • Industry will collaborate with CDISC to create, govern, and maintain the Rules.
  • Microsoft will develop the Rules’ execution engine and interface.



The following diagram identifies the project teams:

Team Diagram


CORE Program Roadmap

Core Roadmap


  • The open-source CORE Minimum Viable Product (Evaluation Release 0) will be developed during the 9 months between Q3 2021 and Q2 2022. This will include two deployments: (1) CDISC-provided public cloud evaluation environment, and (2) Private cloud evaluation environment.
  • Following the evaluation period, CDISC will continue to maintain the open-source CORE engine under COSA (CDISC Open-Source Alliance), and will assist the vendor and sponsor community as they begin to extend the CORE system.
  • It is difficult to specify a precise timeline for extensions to the CORE engine because for the most part they will be developed by third parties (vendors and sponsors); however, as a strawman timeline for consideration:
    • CDISC projects third parties to provide engine extensions during the one-year period of Q3 2022 to Q2 2023. During this period, CDISC will develop the Conformance Rules for the remaining Foundational Standards not covered during the MVP period.
    • CDISC projects third parties to then add more “ease of use” features to the CORE engine during the next one-year period from Q3 2023 to Q2 2024. During this period, CDISC will release new Conformance Rules as it releases new standards.


How to Participate

We invite your organization to participate in this exciting new project.
Please visit the CORE Project Participate tab to learn more.

Additional Resources

CORE Charter

CDISC CORE Presentation at 2021 US Interchange

CORE Press Release


The CORE Project seeks volunteers for our Conformance Rules Development Team

  • Mission:
    • Develop the rules specification and the executable form of the rules
  • Work Areas:
    • Specification structure and content
    • Executable rules content
  • Roles and Experience:
    • Rule Developer
      • Experience developing conformance rules and/or using conformance rules to check clinical data
      • Knowledge of SEND, SDTM, or ADaM
      • Experience with regulatory submissions

Expected Engagement

  • Time Period: 3 - 6 months, or longer, if able
  • Hours per week: 2 - 4 hours, in addition to meeting attendance
  • Weekly Meetings and Workshops: Recorded and available for review

CORE Volunteer Onboarding Training Webinar

Join us 7 June 2022 for an Onboarding Webinar where we will explain tools and processes that will prepare you serve with our very active, global team. The webinar will be followed by a Q&A session; you can submit questions for the Q&A session in advance of the webinar when you register.

Sign-up Instructions

  • If you would like participate in this exciting effort, sign up on the CDISC volunteer page and indicate CORE on the form as the Standards Development team. Please include which CORE team you would like to join in the box at the bottom of the page.

CDISC held a webinar 20 July 2021 to provide a deeper understanding of the CORE project, share the “ask” of participants and answer questions from attendees. We invite you to listen to the webinar recording to learn more.

Library Access Cost

Will a subscription to the CDISC Library be required to develop/use CORE?
  • Before CORE is deployed, CDISC will implement a version of the Library accessible to non-members to ensure that the access needed to use CORE is available to all.
  • A CDISC Library API key, accessible through a Library account, will be required for CORE to retrieve executable rules and standards.

Data Format

What data exchange formats will CORE support?
  • CORE will ingest a variety of dataset formats, including SAS v5 XPORT, Dataset-XML, Dataset-JSON, and CSV.
  • As an open-source application, vendors can extend CORE to add support for additional dataset formats.

Executable Rules Language

In what computer language will the CORE executable conformance rules be written? Will the executable rules be system agnostic?
  • Most of the Conformance Rules will be written as metadata executable by the CORE engine.
  • This way, a majority of the project volunteers will be able to develop these executable rules without deep knowledge of a particular programming language.
  • The metadata will be tested and validated with the CORE engine.
  • The CORE engine will provide a framework to plug-in new rule types developed by the CORE team or by other implementers that have the need for additional types of rules.
  • CDISC plans to only test and validate the executable rules metadata with the CORE engine; however, vendors and sponsors will have the option to develop their own applications to work with the open-source executable rules metadata

Format Reports

In what output formats will the CORE reports be available?
  • CORE reports will initially be produced in Excel to facilitate day-to-day operations by CORE users.
  • CORE plans to support SDRG-XML so that the output of the rule execution will be available in a reviewer’s guide format.
  • More technical outputs such as XML, JSON, and CSV are planned for later CORE versions or update release.
  • Vendors and sponsors will have the ability to extend the open-source CORE engine to provide reports in additional output formats.


How can these rules and open-source technology be integrated with current operational clinical data systems?
  • The executable Conformance Rules will be available in the CDISC Library, and a rich set of APIs will be provided for the CORE engine to access these rules.
  • The open-source CORE engine can be integrated into or run by existing clinical data systems to add a standards conformance capability.
  • The CORE system will also provide an API to enable integration with existing clinical data systems.
  • In other words, users can create hard endpoint integrations or API endpoints for the CORE engine with their existing systems.

Relationship to Commercial Systems

How does CORE relate to open-source and commercial systems available today?
  • The CORE engine will be open-source, available to all. It will not be offered by CDISC as a commercial product.
  • The CORE engine will be designed execute the CDISC Conformance Rule sets.
  • The CDISC Conformance Rules will be an integral part of the CDISC Standards; they will be developed by CDISC with the Community and will be governed by CDISC standards development processes.
  • The CDISC Conformance Rules will be an unambiguous, executable set of rules for CDISC Standards.
  • The Conformance Rules for new CDISC Standards will be developed and released in a timely manner (i.e., as the new standards are released).
  • The CDISC Conformance Rules will be a single source of truth, open-source and available to all in the CDISC Library.
  • The CDISC Library will provide a rich set of APIs to access the CDISC Conformance Rules.
  • The CDISC Conformance Rules will be expressed in a common/layman language.
  • Vendors and sponsors will be able to integrate the open-source CORE engine into their operational systems.

Regulatory Agency

How do you see the involvement of Regulatory Agencies?
  • We would expect the Regulatory Agencies to be involved in this project to ensure that their requirements are met.
  • CDISC will work closely with the Regulatory Agencies to ensure the necessary guidance and input for the conformance rules to be compliant with published requirements for each agency
When the Regulatory Agencies do use CORE, will that use replace their current use of any other Conformance Rules systems?

At the time this response is being written (July 2021), the CORE project is just launching and the Regulatory Agencies have not yet determined their participation in the project or their future use of CORE vis-à-vis their use of any other Conformance Rules systems.

Will the CDISC Conformance Rules account for the Regulatory Agency-specific rules from Technical Conformance Guides and/or technical rejection criteria?
  • Yes, CDISC expects to include Regulatory Agency-specific rules within its full set of rules in CORE.
  • It is expected that the user can run this specific rule set on the data.
  • It is expected that these rule sets will be based on the relevant agency requirement documents.
When Regulatory Agency-specific conformance rules conflict with CDISC Conformance Rules, will the Regulatory Agency rules supersede the CDISC Rules?
  • There are small but important implementation differences between the CDISC standards and the regulatory agencies implementation.
  • Even-though CDISC will continue to work with the Agencies to minimize the difference in implementations, it is expected that differences will continue to exist.
  • It is expected that the user will have the option to check the conformance of the data against multiple rulesets, and the user will be able to configure the rule sets to meet their needs, such as disabling a conflicting rule.
Will technical support be provided to Regulatory Agencies for their use of the CORE engine?

Yes, CDISC would ensure appropriate technical support is provided for future use of CORE by the Regulatory Agencies.


What is the planned timeline of the CORE project?
  • The open-source CORE Minimum Viable Product (Evaluation Release 0) will be developed during the 9 months between Q3 2021 and Q2 2022. This will include two deployments: (1) CDISC-provided public cloud environment, followed by a (2) Virtual private cloud evaluation environment.
  • Following the evaluation period, CDISC will continue to maintain the open-source CORE engine under COSA (CDISC Open-Source Alliance) and will assist the vendor and sponsor community as they begin to extend the CORE system.
  • The CORE roadmap also identifies two subsequent releases, R1 and R2, with additional features defined. CORE uses an agile development methodology, and the timelines for these releases will be developed as part of future release planning sessions.

Volunteer Information

What will the 20% FTE effort look like and for how long is it needed?
  • CDISC is seeking volunteers who can make a significant investment of time in the project, in order to complete the Minimum Viable Product (Evaluation Release 0) in the 9 months between Q3 2021 and Q2 2022. A volunteer effort of at least 20% FTE will represent such an investment.
  • The delivery of the 20% FTE effort will vary from week to week. It will include some time in team meetings and some time in independent development work. Some weeks might involve more hours of work than others.
What technical skills are needed to participate?
  • CDISC anticipates that most volunteers will be members of the Conformance Rules Development team or the Quality Assurance Team.
  • The Conformance Rules Development team seeks people who have experience using conformance rules to validate standard clinical data or authoring conformance rules. The executable rules will be written as metadata and will not require skills in one particular programming language. Experience developing test data is also desired.
  • The Quality Assurance team is looking for people who have experience validating clinical data systems. This experience might include designing and authoring a validation plan, authoring test scripts, designing and developing test data, reviewing system validation results, and preparing a final validation package.
How can we volunteer?

Those interested in participating in the CORE project can express their interest by visiting the Participation tab and following the instructions.

Webinar Recording

Is a recording of the CORE webinar available?

Yes, the webinar was recorded, and is accessible on the Webinar tab.


I would expect that the implementation of the rules will identify gaps/errata in the SDTMIG 3.4. Is there a planned feedback and development cycle for the ruleset to progress hand-in-hand with the CORE initiative?

Going forward, the development cycle for the Conformance Rules will become a normal part of the standards development.

Good to see Evaluation Release 0 (Q3 2021 - Q2 2022) aims to implement conformance rules for SDTM v2.0 and SDTMIG v3.4. What is the timeline for users be able to configure customized rules?
  • Evaluation Release 0 is the Minimum Viable Product with basic conformance checking functionality. There will be two deployments of the MVP: (1) CDISC-provided public cloud environment, and (2) Private cloud evaluation environment.
  • Users will be able to provide their own conformance rules in the private cloud deployment, which will be released shortly after the CDISC-provided deployment.
  • Complete conformance checking functionality will then be available in Production Release 1, which is projected for Q2 2023.
Can the tool be available as desktop tool also?
  • CORE will be developed for the cloud and will ingest locally maintained data. Initial deployments include public and virtual private cloud-based solutions.
  • A range of future cloud and on-premises deployments are planned, including a virtual machine-based laptop deployment.
The CDISC Conformance Rules will be metadata that resides in the CDISC Library. Will the sponsor-specific rules also reside in the CDISC Library?
  • The CORE engine will be designed to run conformance rules from the CDISC Library, as well as sponsor-defined rules. Sponsor-defined rules will not be maintained in the CDISC Library.
  • CORE plans to include Conformance Rule authoring tools that support the development and testing of both CDISC and sponsor-defined rules.
How to build the sustainability of this open-source project?
  • CDISC has initiated the CDISC Open Source Alliance to support and promote open-source software developed for the CDISC standards. CORE will be included in COSA.
  • COSA will plan community building activities such as hackathons, workshops, conference sessions, and webinars to help build the CORE open-source community.
  • CDISC will continue to develop CORE as part of the open-source community.

CORE Minimal Viable Product (MVP)

Run conformance checks on sample CDISC datasets to explore the CORE MVP's features and functionality. CORE MVP is freely available to employees of CDISC members and non-members.

Access: You will need a CDISC Library account to log into CORE. If you already have a Library account, please use that to log into CORE. If you do not have a CDISC Library account, you can create one using the Sign Up link at the CORE Log In screen.


Questions and Feedback: Please complete our contact form to share feedback or ask questions.

View the CORE Tutorial