Latest page content update: 24 Nov 2022

Page Note:

The CORE project originated as a traditional CDISC project with planning and volunteer/collaborator recruitment during spring & summer 2021 and formal kickoff in Sept 2021. During summer 2022, CDISC transitioned CORE development to an open-source framework. This page (tab) describes the project goals, objectives, and high-level roadmap; Please see the Program Governance page (tab) for description of the open-source governance framework. Please see the Planning & Status page (tab) for the latest CORE activity, which is now guided by the open-source CORE Roadmap Board.


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 Reference Implementation of an open-source execution engine for the executable Rules.

CDISC has collaborated with Microsoft and other organizations 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 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
  • Create a Reference Implementation of an open-source engine that executes the Rules
  • Release the open-source engine under the CDISC Open-Source Alliance (COSA)

Further Considerations

  • The CORE project includes development of:
    • Executable Conformance Rules for the CDISC standards
    • A Reference Implementation of a software engine (CORE) to execute these rules
  • CDISC is publishing the executable Conformance Rules in the CDISC Library
  • CDISC provides free access to CORE to CDISC members and non-members
  • CORE is published as open-source (MIT license)
  • CDISC has no plans to deploy CORE as commercial software
  • Developers have the option to prepare CORE for:
    • On-premises deployment
    • A cloud-platform deployment
    • Running from command line, integrating with other systems
  • Implementers may choose to develop a proprietary engine or adapt CORE
    • The CORE Engine Reference Implementation can confirm that a proprietary engine achieves the correct results

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:

CORE Concept Diagram


CORE Program Roadmap

The following graphic describes the CORE Program Roadmap.

During the first phase (Evaluation Release 0):

  • The initial open-source CORE Engine was developed during the 9 months between Q3 2021 and Q2 2022. This included two deployments: (1) CDISC-provided cloud evaluation environment, and (2) Azure Marketplace cloud evaluation environment.
  • The initial set of executable Conformance Rules was developed (for SDTM).
  • All work in the Evaluation phase was done as a traditional CDISC project, assisted by its collaborators and volunteers.

The second phase of CORE (Production Release 1) has recently begun. In this phase:

  • The CDISC Standards team will develop the Conformance Rules for the remainder of the Foundational Standards not covered in the Evaluation phase.
  • The CORE Reference Implementation Engine has been registered with COSA (CDISC Open-Source Alliance). Further development and maintenance of the CORE Engine Reference Implementation is being conducted in the new CORE open-source framework, guided by the CORE Roadmap Board.
  • The vendor community has begun to deploy the CORE Engine in various environments and in some instances provide Engine extensions. Some sponsors (end-users) are expected to do their own deployments without vendor assistance.
  • 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.
    • 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

CORE Press Release

Exciting Project News

  • The first free, publicly available CORE Engine desktop deployment by an industry software vendor (Formedix) is now available!
    • Formedix uses a technology preview version of the CORE Engine to which it has added its own user interface. This simple-to-install and use desktop version makes it easier for users to evaluate the CORE Engine and Rules without IT support. Formedix discusses this CORE offering in a blog post.
    • The public can download the offering via the Formedix website here. The download package includes test data publicly available from CDISC to jumpstart use; user study data can also be referenced. This Formedix CORE offering accesses all the CORE Rules currently available in the CDISC Library (at time of release).
  • The uptake of CORE by the CDISC community is already under way!
    • CDISC received a significant number of CORE presentation abstracts for the 2023 Europe Interchange and for the first time the Interchange featured two dedicated CORE sessions!
    • The first session focused on CORE Rules development and included CDISC staff presentations by Chief Standards Officer Peter Van Reusel and Heads of Standards Development Amy Palmer as well as a presentation by a dedicated CDISC volunteer whose company has been involved in CORE Rules authoring and implementation.
    • The second session focused on CORE implementation. The session started with a CDISC staff presentation by VP of Data Science Sam Hume and continued with four presentations by organizations who are working on integrating CORE into their clinical data application platforms.

CORE Next Steps

  • Work toward completing the executable Conformance Rules for the Foundational Standards as well as the Regulatory business rule sets, targeting a complete set of Conformance Rules by the end of 2023. The completion date of this milestone is largely dependent on the number of volunteers actively working to develop the rules.
  • Update the CORE Engine and Rule Editor with the necessary new functionality as new Conformance Rule requirements emerge.
  • Implement a formal governance process for Conformance Rules.
  • Continue dialog with software vendors considering development of CORE offerings.
  • Implement a certification program for proprietary Rule execution engines.
  • Continue dialog with Regulatory agencies toward eventual adoption of the CORE Rules.
  • Provide a validation package for CORE that implementers can extend to offer a fully validated solution.


Summer and Fall 2021:

  • Development began on a minimum viable product (MVP) Rule Editor and execution Engine.
  • Conformance Rule authoring began as the earliest versions of the Rule Editor and Engine became available. The initial rule authoring focus was on Rules for the SDTMIG 3.4.

2022 CDISC Europe Interchange, April 2022:

  • The first deployment of the MVP CORE Engine, a minimum-featured evaluation version in the CDISC cloud and free to all, was announced and demonstrated.
  • About two-thirds of the 336 executable rules in SDTMIG 3.4 were published in the CDISC Library and accessible via Library API as well as to the CORE Engine and other software tools.

Summer 2022:

Fall 2022:

  • Initiated Conformance Rules development for remaining CDISC Foundational Standards
  • Initiated ongoing dialog with FDA about eventual CORE Rules adoption.
  • Discussed early provision of the CORE Engine with industry software vendors, with focus on desktop versions that are easy to deploy and feature a user interface of the vendor’s design. These simple to install and use desktop versions will make it easier for the CDISC community to evaluate the CORE Engine and executable Rules and provide valuable feedback to CDISC.

Volunteers are needed for Conformance Rule development. To sign up, please visit the “Participate” tab.

Latest page content update: 24 Nov 2022

Project milestone reached: 28 April 2022

Evaluation version of CORE Engine Reference implementation was deployed on CDISC’s Azure cloud subscription:

  • Available to users for free
  • Initially includes 200+ Rules for SDTMIG v3.4
  • Test data is provided by CDISC; users cannot provide their own data
  • Visit the TRY IT NOW tab to access this deployment

Project milestone reached: 31 August 2022

Transition of the CORE Engine Reference Implementation to the open-source environment was completed with provision of the Engine in GitHub. The Engine is:

CORE Rules Development

Rules Planning

  • An inventory of Rules per Foundational Standard has been developed and is presented in the following graphic:


Rule Count by Standard/Version
  • A timeline for development for these Rules has been prepared and is presented in the following graphic. Note that much of the work for SDTM 3.4 has been completed already.
  • The remaining work represented in the timeline is estimated to require about 3.0 FTE for about 8 months, followed by about 1.0 FTE for an additional 6 months. This timeline assumes this level of resourcing will become available to the project.


Rules Status

  • The work on the SDTM, SEND, and Define Cross-Checks has recently begun with the limited number of volunteers currently available.
  • The CORE project is actively recruiting additional volunteers for this work right now. (See the CORE Roadmap Board activities below on this web page (tab) for more about this).
  • A “CORE Volunteer Onboarding Training” webinar for this Rules development was held June 7, 2022. The webinar covered the scope of Rules, the Rule Editor for authoring and testing Rules, and how to sign up and participate. Listen to the CORE Volunteer Onboarding Training. We invite you to visit the Participate tab to sign up to participate on CORE.
  • Beyond the webinar, other on-boarding materials to support Volunteers have been delivered:
    • Training materials
    • Quarterly training sessions to onboard new rule authors
    • Rules development workshops at:
      • 2022 CDISC US Interchange
      • 2022 PHUSE EU Connect

CORE Engine Development

Engine and Deployments Planning and Status

  • The evaluation version of the CORE Engine Reference Implementation was previously deployed to the CDISC cloud subscription (April 2022) and to the Azure Marketplace (June 2022).
  • Following these deployments, and as part of the transition of CORE from a traditional CDISC project to an open-source framework, CDISC has released the Engine on GitHub.
  • Going forward, the open-source Engine development community will be responsible for future Builds of the Engine. These Builds will continue to improve functionality and features of the Engine, as needed. The team anticipates multiple Beta releases with less frequent Stable releases made available. All Engine Builds will be made available on GitHub.
  • Engine deployments will be the responsibility of the users. This will include end-users such as Pharma-Biotech and CRO organizations as well as commercial software vendors and integrators deploying for end-users.
  • Currently, several vendors have confirmed they will publish free desktop deployments. More communication is expected to follow.
  • In addition, the CORE project anticipates that a small number of end-users will integrate the Reference Implementation into their environment during 2023.
  • The following graphic illustrates this planning:


Latest page content update: 24 Nov 2022

Open-Source Governance and Development

During the summer of 2022, after completion of the initial set of executable Conformance Rules (for SDTM 3.4) and release of the evaluation version of the CORE Engine Reference Implementation, CDISC transitioned the CORE project from a traditional CDISC-led project to an open-source framework. The transition focuses on:

  1. Establishment of a CORE Roadmap Board and CORE Technical Committee to guide and coordinate further Engine Reference Implementation development as open-source and to coordinate with CDISC on CDISC’s further Conformance Rules development.
  2. Establishment of the CORE Engine Reference Implementation software as open-source by making it publicly available in GitHub and registering it with COSA (CDISC Open-source Software Alliance). Further Engine Reference Implementation development will be conducted under the MIT open-source license by a volunteer, open-source development team.

The following graphic illustrates the full open-source framework for further CORE development. The framework centers on the CORE Roadmap Board and CORE Technical Committee and involves CDISC staff, industry volunteers, and commercial software vendors.


CORE Program Governance

CORE Roadmap Board

The Board is composed of most-engaged CORE stakeholders from Pharma-Biotech, CDISC, Independent consultants, and Service providers. Engaged software vendors have a parallel opportunity to participate today on the CORE Technical Committee and a future opportunity to participate in the CORE Registered Solution Providers program which will be established by the Board.

Following are high-level highlights of the CORE Roadmap Board’s responsibilities:

  • Promote CORE and drive adoption
  • Set strategic vision
  • Oversee Roadmap development
  • Facilitate Engine Reference Implementation development
  • Ensure open, unbiased interaction with vendor community

Following are the CORE Roadmap Board members:

Industry CDISC
Anne-Sophie Bekx, Janssen Dave Evans, CEO
Chris Decker, Instem Sam Hume, VP Data Science
Praveen Garg, Astra Zeneca Peter Van Reusel, CSO
Brooke Hinkson, Merck
Stephen Matteson, Pfizer
Girish Rajeev, Takeda

Board meetings are currently ongoing approximately monthly.


CORE Technical Committee

The Technical Committee is comprised of the most-engaged CORE stakeholders from the CORE Maintainer and Contributor Technical Community. These are the volunteers who are currently most active in the technical side of development of the CORE Engine Reference Implementation.

Following are high-level highlights of the CORE Technical Committee’s responsibilities:

  • Function as the Architecture Review Board
  • Approve architecture decisions
  • Determine the technology stack
  • Resolve development / technology disputes
  • Develop testing strategy
  • Recruit other developers
  • IP and security assessments 

Latest page content update: 24 Nov 2022

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
    • Rule Developer Skill Set
      • Core Skills
        • Data savvy with science background; e.g., statistics, biometrics, data science
        • A CDISC standards practitioner. Solid implementation experience with SEND, SDTM, and/or ADaM
        • Experience in data specifications & associated verification & validation tasks
      • “Plus” Skills
        • Some familiarity with the associated conformance rules
        • Knowledgeable in structured data, such as XML, JSON, YAML
        • A member of an organizational standards council or governance body
      • People without coding experience can succeed in rule development. The carefully prepared initial training program and ongoing support process enable this.


Expected Engagement

  • Time Period: 3 - 6 months commitment, or longer if able
  • Hours per week: efforts such as 20%, 40% FTE will be helpful; smaller FTE efforts are possible
  • Weekly Meetings and Workshops: Recorded and available for review


CORE Volunteer Onboarding Training Webinar

A CORE Volunteer Onboarding Training webinar for the Rules Development was held 7 June 2022. The webinar covered the scope of Rules, the Rule Editor for authoring and testing Rules, and how to sign up and participate. Listen to the CORE Volunteer Onboarding Training.


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.

The following are links to CORE presentations from the 2023 CDISC US Interchange and PHUSE EU Connect, respectively:


The CDISC Open Rules Engine: Open-Source Software for Clinical, an article in Clinical Leader by Sam Hume, VP, Data Science, CDISC

Latest page content update: 15 Jun 2022

Library Access

How do I set up a CDISC Library Account?

Please visit the Try It Now tab to set up an account.

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 and Rules Editor

In what computer language will the CORE executable conformance rules be written? Will the executable rules be system agnostic?

All executable rules for CORE (“Rules”) are expressed in YAML. YAML is a non-proprietary data interchange language. Rules are authored in the Rule Editor, which is an on-line web application. Prior knowledge of any programming languages is not required to author Rules in the Rule Editor. All Rules are based on one data model, from which we deduce a schema. This schema is the backbone of the Rule Editor, providing syntax hints and validations.

CDISC maintains rule sets along with publication of foundational standards. Many conformance rules in these rule sets can easily be transcribed into metadata and rule logic, whose structure is bound to the schema. Schema validated Rules are sent to the CORE Rule Engine (“Engine”) for execution.

The Engine provides 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 Rules with the Engine; however, vendors and sponsors will have the option to develop their own applications to work with the Rules, under an open-source arrangement.

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.

Access to CORE Source Code via GitHub

How can I access the CORE source code to implement my own conformance checking tool?

CDISC will provide details when the CORE source code is released as open-source on GitHub.

Will CDISC provide GitHub training when CORE is released as open-source as GitHub?

Yes, CDISC will provide GitHub training when CORE is released as open-source on GitHub.


Is the CORE API based upon the REST standard?

Yes, CORE has a REST API.

Validation of a CORE Implementation

How can I confirm that my implementation of the CORE engines works correctly?

CORE will include a suite of automated tests that can be used to help confirm that a CORE implementation is functioning correctly. CDISC also plans to implement a certification program to verify that software that executes the Conformance Rules functions correctly and consistent with the CORE Reference Implementation.

If companies/organizations develop their own engine, how is it guaranteed that this implementation obeys (i.e. gives the same results) as the reference implementation?

CDISC plans to implement a certification program to verify that any software that executes the Conformance Rules functions correctly and consistent with the CORE Reference Implementation. All CORE Certified software engines will demonstrate that they yield the same results given the same set of rules and CDISC datasets.

Data Security

How does CORE handle data security?

CORE has undergone a security review and comprehensive threat assessment to identify and address vulnerabilities. The CORE architecture addresses stringent data and application security requirements to ensure that CORE can be deployed in a highly-secured and validated environment. Since CDISC will not provide a production deployment of CORE, each implementation should be evaluated to ensure the environment meets all identified security requirements. Given the detailed nature of software and data security, CDISC plans to publish a white paper to provide a comprehensive response to address CORE security questions.


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.

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?

CORE will be released as an open-source project under the MIT license, and we will continue to grow the community of volunteer developers, rule authors, and testers that have contributed to CORE's development thus far. As we transition to open-source development and governance models, additional roles and opportunities will emerge for CORE contributors. Over 80 volunteers from over 50 companies have contributed to CORE development to date. If you're interested in joining us, please check out the CORE page.

CDISC has initiated the CDISC Open Source Alliance (COSA) to support and promote open-source software developed for the CDISC standards, including the CORE project. COSA will plan community building activities such as hackathons, workshops, conference sessions, and webinars to help build the CORE open-source community.

Latest page content update: 01 Mar 2023

CORE Engine Reference Implementation in GitHub

The CORE Engine Reference Implementation is the current version of the Engine. The CORE Engine Reference Implementation has been transitioned to the open-source environment with its provision on GitHub. The GitHub-based Engine is:

The CORE Engine Reference Implementation on GitHub is an advancement over the CORE Minimum Viable Product (MVP) Engine early evaluation version that was previously available via the CORE web page. In particular, the GitHub-based Engine is updated to process additional Rule syntax (YAML) engaged to handle new processing conditions that were encountered as the CORE team developed additional Rules.

The GitHub-based Engine is provided with a command line interface (CLI) and not with a Graphic User Interface (UI). The earlier MVP version had been provided with a basic UI to allow users to quickly and easily run the Engine to provide early feedback on the Engine functionality to the CORE team. Provision with a CLI provides implementers with the maximum flexibility while integrating the CORE Engine into their processing environments.

The GitHub-based Engine with its CLI, in general, has functionality like that seen in the earlier MVP version. A pre-recorded CORE Tutorial, which was prepared while running the earlier MVP Engine version, demonstrates the basic Engine functionality that is available in the GitHub-based version. You can view that tutorial just below on this page.


View the CORE Tutorial


Copy here.