New here? Start with the tutorial
USDM Tutorial sequences every lesson on this hub into one ordered learning path: Concepts → Model → Build → Validate. Or jump straight to What is USDM? if you just want the one-page answer.
Learn the basics
What is USDM?
The one-paragraph definition, the backbone, and what a USDM study actually contains.
Read the lesson →Why was USDM created?
The DDF history, the ICH M11 connection, and the 'write once, read many' motivation.
Read the lesson →USDM vs SDTM
Planned design vs. collected data, with a full field-level mapping table.
Read the lesson →USDM vs ODM
Reference model vs. transport model, and where SDM-XML overlaps.
Read the lesson →CDISC DDF Explained
The Digital Data Flow initiative, its four phases, and the SDR.
Read the lesson →CDISC 360 Explained
How USDM feeds end-to-end standards automation via Biomedical Concepts.
Read the lesson →Understand the model
USDM Object Model
The ten model areas, standard attributes, and complex datatypes.
Read the lesson →USDM UML Tutorial
How to read cardinalities, inheritance, and naming conventions.
Read the lesson →USDM Relationships
Arm×Epoch=Cell, Cell→Element, Encounter↔Epoch, Timing.
Read the lesson →USDM Validation
CDISC's CORE conformance rules, with real rule text and severity levels.
Read the lesson →Implementation Guide Explained
A section-by-section walkthrough of the USDM-IG.
Read the lesson →USDM Version 4.0 Explained
What's new in v4.0, and the full version history.
Read the lesson →Build with USDM
USDM Examples
Five fully worked study designs, from parallel arms to conditional branching.
Read the lesson →USDM JSON Examples
Annotated payloads for every class you'll touch most, plus downloads.
Read the lesson →USDM API Tutorial
Serialization rules, Id/Ids cross-references, and the extension mechanism.
Read the lesson →USDM Use Cases
Real automation: SDTM generation, EDC set-up, patient journeys, feasibility.
Read the lesson →USDM Tutorial
A single ordered learning path through every lesson on this hub.
Read the lesson →USDM Training
The ten-chapter official curriculum, mapped to lessons here.
Read the lesson →Frequently asked questions
What is USDM in one sentence?
USDM (Unified Study Definitions Model) is CDISC's data standard for representing a clinical trial's design — objectives, arms, epochs, visits, schedule of activities, and estimands — as structured, machine-readable data instead of a static protocol document.
Is USDM Play affiliated with CDISC or TransCelerate?
No. USDM Play is an independent educational resource covering CDISC USDM, the Digital Data Flow (DDF) initiative, and ICH M11. For official, authoritative deliverables, see CDISC's cdisc-org/DDF-RA GitHub repository and TransCelerate's ddf-home repository.
Where should a complete beginner start?
Start with What is USDM?, then follow the USDM Tutorial learning path, which sequences every page on this hub from concepts through the object model to building and validating your own USDM JSON.
Does this site have downloadable USDM JSON examples?
Yes — USDM Examples and USDM JSON Examples both include complete, annotated, downloadable sample JSON files covering a full study design, a timing sub-timeline, and a biomedical concept structure.