CDASH stands for Clinical Data Acquisition Standards Harmonization and is a CDISC standard for the structured collection of clinical trial data. It defines standardized questions, variables, and metadata for Case Report Forms, particularly for electronic CRFs in EDC systems. CDASH aims to ensure that the same clinical information is consistently labeled at the point of capture and can be unambiguously used for subsequent tabulation.
Its value therefore lies in the content-standardized question before a data value even enters the database.
Starting Point of the Standardized Data Chain
CDASH applies where investigational sites enter data or transfer it from source documents: for demographic information, adverse events, concomitant medication, laboratory values, and other study observations. The model does not prescribe medical treatment but organizes the data elements used to document an observation. A CDASH-compliant form can therefore shape the structure of an eCRF without dictating its screen layout.
For each domain, the Implementation Guide identifies collection variables and supplements them with metadata tables. The normative table and the explanatory guide content must be used together. The standard thereby supports planning work before the first patient entry: for each question, it can be clarified which concept is being captured, which response format is permissible, and how the information should subsequently be processed.
Alignment with SDTM and Controlled Terminology
CDASH uses the same observation classes and domain concepts as the SDTM Implementation Guide. This alignment facilitates mapping from the collection field to the subsequent tabulation variable and makes the origin of data more visible across the data flow. However, it does not mean that every form field must be an identical copy of an SDTM variable; the purpose of data collection may impose additional practical requirements.
Controlled terminology also plays a role in form design. Where CDISC value lists are specified, collection should use the standardized submission values or appropriate synonyms. This limits free-text variants and subsequent recoding work. For data management teams, it is particularly important that edit checks, selection lists, and annotations align with these specifications.
Standardization does not begin only with the field name. For proper implementation, each question must have a technical definition: it must be decided whether, for example, a date of observation, documentation, or drug administration is being captured. CDASH metadata help make these distinctions visible in the form specification. This reduces the risk that different sites interpret similar fields differently.
For external data sources, CDASH remains a reference point even when no investigator completes a corresponding form. The specification can define how a centrally collected value corresponds to the concept expected in the eCRF. This does not eliminate the need for subsequent SDTM mapping but allows it to rely on clearer, pre-agreed assignments.
Distinction from eCRF and SDTM
CDASH is not the Case Report Form and is not a specific EDC product. The Case Report Form or electronic Case Report Form is the actual form used by an investigational site in a study. CDASH provides the standard behind the fields, questions, and metadata of that form.
Compared to SDTM, CDASH stands at the beginning of the data chain. CDASH structures how information is queried; SDTM organizes already collected or transferred data for tabulation and submission. When both standards are deliberately aligned, the scope of subsequent mapping decreases. Nevertheless, data cleaning, coding, specifications for external data sources, and SDTM transformation remain independent work steps.
Training materials for investigational sites also benefit from a clear data collection definition. They explain not only the click path in the EDC but also when a clinical observation belongs in a specific field and when a query is required.
Relevance for clinical trials
A CDASH-oriented eCRF design compels the project team to define data collection precisely before study start. Medical questions, protocol requirements, planned endpoints, and subsequent SDTM objectives must be integrated. Typical risks include inconsistent response lists, field names without clear definitions, and subsequent form changes that create different data states. An annotated CRF therefore forms a central bridge between investigational sites, data management, and submission programming.
Full-service CROs such as Mediconomics support CDASH-aligned studies with CRF design, creation and review of CRF completion guidelines, EDC configuration, edit check specifications, and annotation for SDTM transition. They also align form fields with coding concepts, central laboratory requirements, and investigational site data flows so that collected values transition into subsequent datasets without semantic breaks.
Frequently Asked Questions (FAQ)
Does CDASH specify which endpoints a study must have?
No. CDASH standardizes the collection structure. The scientific selection of endpoints, assessments, and study procedures is determined by the protocol and clinical development strategy.
Must every eCRF fully comply with CDASH?
Implementation depends on the study purpose and requirements. CDASH provides a common basis particularly for frequent clinical concepts, which can be supplemented on a study-specific basis.
Why is CDASH annotation important?
It shows how a form field is connected to standardized variables and domains. This facilitates review of data collection and subsequent SDTM specification.
Regulatory References
- CDISC CDASH Model – defines the model for standardized data collection fields.
- CDISC CDASH Implementation Guide – explains implementation in Case Report Forms and metadata tables.
- CDISC Controlled Terminology – provides standardized value lists for relevant collection concepts.
- CDISC SDTM Implementation Guide – forms the subsequent tabulation structure to which CDASH is aligned.
