Welcome to Digital Data Flow (DDF) for Clinical Trial Protocols
Digital Data Flow Initiative will help modernize clinical trials by enabling a digital workflow with protocol digitization. This initiative establishes a foundation for a future state of automated & dynamic readiness that can transform the drug development process.
Below are a list of the different websites sourcing specific content and resources. Depending on where you are in the journey, please feel free to explore the different websites and their information.
 CDISC DDF Website | DDF Website | DDF GitHub Repos | TransCelerate DDF Initiative Solutions |
Target Audience: | Target Audience: | Target Audience: | Target Audience: |
CDISC is collaborating with TransCelerate through TransCelerate’s Digital Data Flow Initiative to develop a Study Definition Reference Architecture called the Unified Study Definitions Model. The USDM will serve as a standard model for the development of conformant study definition technologies.
Visit the What is USDM and Versions tabs to learn more about the USDM and released versions of USDM. Also visit the CDISC DDF GitHub site to follow the development activities of the USDM.
To learn more about DDF, go to the DDF Website.
Roadmap and Upcoming Activities
Phase 1: | The Reference Architecture (RA) provides solution architects with a common vocabulary, reusable designs, industry best practices, standards, and general implementation guidance. The RA is not a solution architecture and is not implemented directly but constrains concrete solution architectures with the purpose of promoting the development of conformant solution architectures that enable interoperability across multiple systems in a clinical study, improve efficiency and data quality, and reduce cycle times. |
Phase 2: September 2022 – July 2023 | Continuing the collaboration with TransCelerate, CDISC has further developed the Reference Architecture. • Introduction of Biomedical Concepts data model • Time Points Data model updates • Electronic Clinical Protocol Template Mapping |
Phase 3: | CDISC has further developed the Reference Architecture with TransCelerate collaboration. • Representation of the draft ICH M11 Protocol template in USDM • Additional model elements for population of SDTM Trial Design Domains with study design information from USDM • Additional model elements for population of Clinical Trial Registry Information (ct.gov) • Model enhancements to enable representation of complex study designs in USDM |
Phase 4: | CDISC is currently developing the scope for Phase 4. Please visit the Participate tab above to become involved in the development and review of USDM 4.0. |
Watch this informational video to find out more about the USDM
Unified Study Definition Model (USDM) Class Diagram
The USDM Class Diagram is a UML Class diagram that functions as the Study Definitions Logical Data Model (LDM). The class diagram as LDM depicts the classes and attributes that represent data entities and the relationships between those entities that are needed to support a conformant Study Definitions application. The class diagram includes a data dictionary that defines each of the classes and attributes to provide the semantics needed to implement the model consistently.
The purpose of the LDM is to provide guidance to the solution implementer. It does not attempt to be inclusive of every class, attribute, and relationship implemented by any given solution. Instead, the LDM describes all elements for a conformant solution based on the Minimal Viable Product. It provides input into the solution architecture with the expectation that every effort will be made to ensure the solution architecture aligns with the RA LDM. The LDM represented by the class diagram may be implemented in a variety of physical data stores, including relational databases, property graph databases, RDF triple stores, document databases, and others. The semantics represented in the LDM and data dictionary support a uniform understanding of the Study Definition data elements to improve interoperability. The LDM will be used to define the resources available in the API specification; these resource definitions represent the data exchange format for applications implementing the API.
The class diagram references industry standards and terminology systems where relevant. For example, the Study Definition class diagram includes references to CDISC Biomedical Concepts, Foundational Standards, and Controlled Terminology. The data dictionary accompanying the class diagram will include references to the CDISC Library for retrieval of all CDISC content. Content from other standards and terminology systems (HL7, LOINC, CPT, ICH M11, et al) may be incorporated into the LDM, with the intention of extending interoperability to data exchange standards, such as FHIR. The class diagram also depicts essential elements of a study protocol including study objectives, endpoints, and the schedule of activities.
CDISC Controlled Terminology to Support USDM
The use of standardized terminology is an essential element of interoperability. To support the Study Definition LDM, CDISC will develop new Protocol Controlled Terminology, including code lists and terms as well as changes to existing terms, if needed. Terminology for SDTM Trial Design domains will also be covered in this project.
Application Programming Interface (API) Specification
A standardized API provides a standard interface for a common set of core services that must be supported by all conformant solutions. A standard API will enable application developers to build solutions that can use the core services of any conformant Study Definition. Data standards, controlled terminology, data exchange standards, and APIs work together to create an optimal environment for interoperability between conformant systems.
A Study Definition REST API will be specified using the OpenAPI Specification (OAS) version 3.0. As a machine-readable format, OAS can be used to generate not only interactive documentation but also source code to aid developers creating software implementing the specification. The CDISC Library also publishes API specifications using these formats. The CDISC Library, HL7 FHIR, and the DDF Study Definition API form a growing set of standard APIs to improve interoperability and automation in clinical trials. Much like the CDISC Library API, the Study Definition API will support a range of media types, including JSON and XML.
The Study Definition API enables clients to create, update, and remove Study Definition content assuming the user’s role permissions support the activity. Accordingly, the API provides access to Study Definition services so that alternative user interfaces and applications can be developed to extend or exchange information with any given Study Definition tool.
Unified Study Definition Model Implementation Guide (USDMIG)
A new deliverable for the Digital Data Flow Reference Architecture v2.0 is a corresponding Implementation Guide. The Unified Study Definitions Model Implementation Guide (USDMIG) is intended for companies and individuals involved in the set-up of clinical studies—sponsors or stakeholders involved in upstream (protocol and content authoring tools)—and downstream consumers of system (e.g., electronic data capture, clinical trial management, trial master file) and document (e.g., protocol, clinical study reports, statistical analysis plans) standardized digitized study definitions.
This document provides users with sufficient information to understand the USDM and also its potential implementations with the study design process by showing examples of the types of study definition information that can be represented in the USDM.
We are looking for targeted reviewers of the draft deliverables throughout the development phase with particular expertise in the following areas:
- CDISC Protocol-related Controlled Terminology
- UML model review in relation to study/protocol concepts
- Technical skills to review API specifications in relation to study/protocol concepts
- Experience of this type of project within your own organization
Anticipated Timelines for Phase 4:
- Development Activities begin April 2024.
- 30-day Public Review is planned for Q1 2025.
Public Review time commitment is estimated at 10-20 hours depending on experience with the four areas mentioned above. We encourage reviewers to reach out to colleagues who may also have experience in reviewing these types of deliverables or have business experience with this type of project. Please get in touch using the sign-up instructions below.
Participate
- If you would like to participate in this exciting effort, please follow the instructions below:
- Targeted Public Reviewers: Sign up on the CDISC Volunteer page and indicate DDF as the Standards Development team. Please enter Targeted Internal and Public Reviewer in the box "Specify in which capacity you want to participate."
- Participation in Standards Development: Sign up on the CDISC Volunteer page and indicate DDF as the Standards Development team. In the specify box enter in what capacity you feel you can contribute to the team and the amount of time you can contribute to the project.
Keep up to date with current USDM development activities from the CDISC DDF Webinars below:
DDF Phase 4 Webinar
Watch the DDF Phase 4 Informational Webinar
DDF Phase 3 Webinar
Watch the DDF Phase 3 Public Review Webinar
Watch the DDF Phase 3 Informational Webinar
DDF Phase 2 Webinar
Watch the DDF Phase 2 Public Review Webinar
DDF Phase 1 Webinar
Watch the DDF Phase 1 Public Review Webinar
Watch the Project Information and Call for Volunteers Webinar
Released Versions of the Unified Study Definitions Model (USDM)
Versions | Release Date | Information |
|---|---|---|
USDM v3.0 Conformance Rule Specifications | 18 December 2024 | Conformance Rule Specifications to support USDM v3.0 • USDM v3.0 Conformance Rule Specifications Comments from the Public Review • USDM v3.0 Conformance Rule Specification Public Review Comments |
USDM v3.0 | 16 April 2024 | USDM Implementation Guide - An implementation guide to support usage of the USDM • USDMIG v3.0 USDM Logical Model • in .png (picture) format API Specifications Controlled Terminology - supporting the UML/API • Controlled Terminology - supporting the UML/API Comments from the Public Review |
USDM v2.0 | 27 June 2023 | USDM Reference Architecture v2.0 |
USDM v1.0 | 9 August 2022 | USDM Reference Architecture v1.0 |
Development activities of the Unified Study Definitions Model (USDM)
Versions | Information |
|---|---|
USDM v4.0 |
Development in Progress
|
Published Date: 27 June 2023
DDF Reference Architecture v2.0 Final
The Digital Data Flow Reference Architecture v2.0 has been released and is available via the Files tab on this page. Key elements include the Unified Study Definition Model (USDM) Class Diagram, the Application Programming Interface (API) Specification, associated CDISC Controlled Terminology, and, new for this release, the Unified Study Definition Model Implementation Guide (USDMIG).
In version 2.0, the USDM has been updated to accommodate more complex study designs, demonstrate population of an electronic protocol template, and expand the model to include a biomedical concept layer to aid in CRF automation.
The USDMIG provides users with sufficient information to understand the USDM and its potential implementations with the study design process by showing examples of the types of study definition information that can be represented in the USDM.
The Reference Architecture v2.0 has completed the CDISC Standards Development Process and is released as Final; the CDISC Controlled Terminology may not be final at the time of release. Additionally, DDF Phase 3 will start July 2023 and build on v2.0. To keep informed of Reference Architecture future enhancements, please attend the informational webinars. Please visit the CDISC RA GitHub Site for ongoing development of Phase 3 of the Digital Data Flow Reference Architecture.
CDISC and TransCelerate have collaborated to develop the USDM Reference Architecture in conjunction with development of a Study Definitions Repository (a reference Implementation of the USDM architecture). For more information on the Study Definitions Repository, please visit the TransCelerate DDF GitHub site and the SDR Github Site.
For any questions related to this release please get in touch using the Contact Us tab. Also if you are interested in becoming part of the DDF team please see the Participate tab for more information.
The DDF Reference Architecture contains the following:
Unified Study Definition Model (USDM) Class Diagram
The USDM Class Diagram is a UML Class diagram that functions as the Study Definitions Logical Data Model (LDM). The class diagram as LDM depicts the classes and attributes that represent data entities and the relationships between those entities that are needed to support a conformant Study Definitions application. The class diagram includes a data dictionary that defines each of the classes and attributes to provide the semantics needed to implement the model consistently.
The purpose of the LDM is to provide guidance to the solution implementer. It does not attempt to be inclusive of every class, attribute, and relationship implemented by any given solution. Instead, the LDM describes all elements for a conformant solution based on the Minimal Viable Product. It provides input into the solution architecture with the expectation that every effort will be made to ensure the solution architecture aligns with the RA LDM. The LDM represented by the class diagram may be implemented in a variety of physical data stores, including relational databases, property graph databases, RDF triple stores, document databases, and others. The semantics represented in the LDM and data dictionary support a uniform understanding of the Study Definition data elements to improve interoperability. The LDM will be used to define the resources available in the API specification; these resource definitions represent the data exchange format for applications implementing the API.
The class diagram references industry standards and terminology systems where relevant. For example, the Study Definition class diagram includes references to CDISC Biomedical Concepts, Foundational Standards, and Controlled Terminology. The data dictionary accompanying the class diagram will include references to the CDISC Library for retrieval of all CDISC content. Content from other standards and terminology systems (HL7, LOINC, CPT, ICH M11, et al) may be incorporated into the LDM, with the intention of extending interoperability to data exchange standards, such as FHIR. The class diagram also depicts essential elements of a study protocol including study objectives, endpoints, and the schedule of activities.
CDISC Controlled Terminology to Support USDM
The use of standardized terminology is an essential element of interoperability. To support the Study Definition LDM, CDISC will develop new Protocol Controlled Terminology, including code lists and terms as well as changes to existing terms, if needed. Terminology for SDTM Trial Design domains will also be covered in this project.
Application Programming Interface (API) Specification
A standardized API provides a standard interface for a common set of core services that must be supported by all conformant solutions. A standard API will enable application developers to build solutions that can use the core services of any conformant Study Definition. Data standards, controlled terminology, data exchange standards, and APIs work together to create an optimal environment for interoperability between conformant systems.
A Study Definition REST API will be specified using the OpenAPI Specification (OAS) version 3.0. As a machine-readable format, OAS can be used to generate not only interactive documentation but also source code to aid developers creating software implementing the specification. The CDISC Library also publishes API specifications using these formats. The CDISC Library, HL7 FHIR, and the DDF Study Definition API form a growing set of standard APIs to improve interoperability and automation in clinical trials. Much like the CDISC Library API, the Study Definition API will support a range of media types, including JSON and XML.
The Study Definition API enables clients to create, update, and remove Study Definition content assuming the user’s role permissions support the activity. Accordingly, the API provides access to Study Definition services so that alternative user interfaces and applications can be developed to extend or exchange information with any given Study Definition tool.
Unified Study Definition Model Implementation Guide (USDMIG)
A new deliverable for the Digital Data Flow Reference Architecture v2.0 is a corresponding Implementation Guide. The Unified Study Definitions Model Implementation Guide (USDMIG) is intended for companies and individuals involved in the set-up of clinical studies—sponsors or stakeholders involved in upstream (protocol and content authoring tools)—and downstream consumers of system (e.g., electronic data capture, clinical trial management, trial master file) and document (e.g., protocol, clinical study reports, statistical analysis plans) standardized digitized study definitions.
This document provides users with sufficient information to understand the USDM and also its potential implementations with the study design process by showing examples of the types of study definition information that can be represented in the USDM.
Volunteering
- Yes, we welcome a variety of feedback from the user community.
- The deliverables for this project are technical automation standards. CDISC is providing workshops during Internal and Public Review to assist in review of the standards.
- We also recommend reaching out to colleagues within your organization who may have expertise in this area from a business and technical perspective.
- This project uses a strict agile methodology. As such, involvement as part of the development team requires significant time commitment (FTE 40% plus).
- Some organizations may already have experience in this type of project and individuals may want to volunteer in a supportive capacity to the standards developers (e.g., performing weekly reviews of the deliverables from each sprint).
- If you are interested in serving on the development team, please visit the Participate tab and follow the sign-up instructions.
- Targeted Reviewer (Internal/Public): 10-15 hours per review.
- Supporting the development team (in a review or protocol SME capacity): FTE 20% or more.
- Participate as a developer: FTE 40% or more.
- Targeted Reviewers do not require specific technical skills.
- Supporting roles for the development team do not require specific technical skills but do require experience working in trial design.
- The Development Team require specific technical skills in the area (for example UML diagram creation in Enterprise Architect, API specification development using SwaggerHub) and preferable experience working in the trial design area.
- Yes, please follow the instructions on the Participate tab.
- For questions about the TransCelerate DDF initiative outside of the work that CDISC is doing, you should contact TransCelerate using the Digital Data Flow Feedback Form.
- No, volunteers on all CDISC teams are welcome from both member and non-member organizations.
Relationship to other Standards
- These standards support the CDISC vision of supporting the implementation of standards.
- These technical standards will be open source and available for all users with alignment with current CDISC standards.
- The USDM is a new technical automation standard, re-using existing standards where applicable.
The new standards will support the development of conformant study definition technologies. Existing standards will be reused where appropriate; the new standards will not replace existing Foundational Standards.
- Yes. The Controlled Terminology developers for this project are also part of the CDISC Protocol Entities team.
- Existing terminologies are leveraged where applicable.
- New terminology developed for this project will follow the standard CDISC Controlled Terminology process.
- Both BRIDG and the USDM are logical data models.
- The USDM is a more practical and implementable model. CDISC is delivering a reference architecture that can immediately be implemented in a reference implementation.
- There are team members involved in the development of the USDM that were also part of the CDISC 360 project.
- The USDM will provide links to future biomedical concept development.
- The USDM will be supported by CDISC Controlled Terminology and external ontologies where appropriate (e.g., study indication).
- The first release of the USDM will focus on the general cross-cutting concepts related to study definitions to be as flexible and useful for all study types.
- No, discussions are ongoing about how the conformant study definition technologies may interact with company-specific eCRFs.
- Independent of this project, CDISC offers the eCRF portal that is freely available for organizations to download eCRF content. eCRFS are added on an ongoing basis.
- Integration with EHRs will be discussed for future iterations, including alignment with Reference Architecture.
- Yes, a list of CDISC, including PRM, and non-CDISC assets related to study design were evaluated as inputs during the scoping process.
Scope
- Additional information on the DDF Project is available on the TransCelerate DDF website.
- The main focus of the initial version will be related to clinical study designs; additional study design aspects, such as nonclinical, will be discussed for future iterations of the USDM.
- Discussions on the different types of studies are currently ongoing.
- The intent is that the USDM will hold those common protocol elements that can be used by other systems or tools such as a digital protocol creation tool and the TransCelerate Common Protocol Template (which is part of the TransCelerate Clinical Content & Reuse Initiative).
- The development of the standards will follow the CDISC Standards Development Process and the governance process defined in the process. CDISC will work with TransCelerate and volunteer Protocol subject matter experts to develop the concepts for the CDISC deliverables.
Technology
- The Study Definition Repository Reference Implementation will be cloud agnostic and open-source; the aim is not to select a particular technology to influence users. The Study Definition Repository will act as a template for use in other technologies. It is a functioning, example approach to connect systems that produce protocol information with those that consume it to drive study operations. Various implementation patterns exist and organizations may or may not choose to implement a stand-alone SDR.
- Upstream and downstream connecting vendors will be involved to provide their input into the deliverables so they can be implemented with connections to many upstream and downstream systems.
- The Reference Architecture provides solution architects with a common vocabulary, reusable designs, industry best practices, standards, and general implementation guidance. Actual implementation of this will vary per company and it is not the intent of this initiative to select a particular technology to influence users.
- Leveraging the latest approved RA version, a Study Definition Repository Reference Implementation has been created by TransCelerate partnering with Accenture to serve as a functioning, example approach to connect systems that produce protocol information with those that consume it to drive study operations. Various implementation patterns exist and organizations may or may not choose to implement a stand-alone SDR.
- The SDR RI is cloud-based, agnostic, and open-source solution using Apache 2.0 open-source license. For more information about the SDR RI, please reference the DDF website
- The open-source license for the Study Definitions Repository Reference Implementation is Apache 2.0.
- The standards developed will be using the CDISC WIKI; volunteers will have access to this area.
- Additional information on the DDF Project is available on the TransCelerate DDF webpage.
- The original rationale for choosing REST over GraphQL is that we're creating a standard API specification that all conformant systems must implement. We anticipate REST will be simpler to produce and govern as a standard specification. It should also allow for the broadest range of implementation support since REST is mature and widely supported across most technology stacks. The decision to use REST also came from early discussions with TransCelerate. CDISC isn’t suggesting that a server can't implement GraphQL, just that the standard API is RESTful. There are pros and cons to each alternative.
- CDISC will deliver a set of conformance tests to ensure that any given Study Definition solution conforms to the DDF Study Definition RA.
- Anyone in the technology community interested in becoming involved in the reference implementation testing should contact TransCelerate using the Digital Data Flow Feedback Form.
CDISC, in collaboration with TransCelerate’s Digital Data Flow Project, is developing a reference architecture, which will serve as a standard model for the development of a Study Definitions Repository. The Repository is a novel central component aimed at facilitating the exchange of structured study definitions across clinical systems using technical and data standards.
Deliverables will include a logical data model, supporting Controlled Terminology, API specifications and related conformance tests. For more information, please read the press release.
CDISC invites you to provide comments on the draft DDF Project Deliverables during Public Review.
- Please visit the DDF Public Review Dashboard page for instructions, timelines, links to the JIRA commenting tool and to deliverables. Please note that this page contains a link to a Public Review Workshop taking place on Monday 4th April 10:00-11:00 EDT. No invites will be sent so please use the Zoom details provided to join this workshop.
- The recording of the Public Review webinar is available at this link .
You will need to log in or register for the CDISC Wiki to provide comments.
- Register for the Wiki. If you already have an account on Wiki or JIRA, our issue-tracking system, simply log in to your account; Wiki and JIRA use the same login credentials. CDISC Wiki is a different login from www.cdisc.org.
Public review is a key quality step in our Standards Development Process. CDISC relies on your input to ensure neutral, consensus-based data standards are developed and adopted by a diverse global community interested in improving research processes and quality for the benefit of all.
Thank you for contributing your time and expertise.