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SDTM 2.2 Datasets and Domains

Each dataset is described by metadata definitions that provide information about the variables used in the dataset. The metadata are described in a data definition document (i.e., a Define-XML document) that is submitted with the data to regulatory authorities. The Define-XML standard (available at https://www.cdisc.org/standards/data-exchange/define-xml) specifies metadata attributes to describe SDTM data.

  1. See the SDTM Define-XML specification (https://www.cdisc.org/standards/data-exchange/define-xml) for details regarding metadata representation when a domain is split into different datasets.




  • The primary use case for Define-XML is to describe CDISC Study Data Tabulation Model (SDTM), 
    Standard for Exchange of Nonclinical Data (SEND), and Analysis Data Model (ADaM) datasets for the purpose of 
    submissions to regulatory authorities. However, Define-XML also serves as a metadata exchange mechanism for 
    other parties seeking to exchange CDISC-modeled dataset structures as well as proprietary (non-CDISC) dataset 
    structures. For dataset structures modeled following CDISC standards, refer to the SDTM, ADaM, and SEND 
    Implementation Guides (IG); see Section 2.2, References.
    The Define-XML model is implemented using extensions to the CDISC Operational Data Model (ODM) XML 
    schema. The intent is to comply fully with all applicable regulations and guidance. This document includes 
    substantially all of the material from the Define-XML v2.0 specification in addition to Define-XML v2.1 changes 
    that include an updated approach to def:Origin, versioning of standards and controlled terminology, improved 
    SENDIG support, v2.0 errata fixes, and additional updates (see Section 1.1.3, Relationship to Prior Define-XML 
    Specifications).
    Define-XML v.1.0 described the requirements for constructing Define-XML documents to replace the define.pdf 
    documents recommended in the FDA’s 1999 Regulatory Submissions in Electronic Format, General Considerations
    guidance (see Section 2.2, References). Since that time, Define-XML documents have proven to be a useful 
    mechanism for transmitting case report tabulation (CRT) metadata. One of the key benefits to FDA reviewers is that 
    this format provides both a machine-readable format for use by the various FDA software applications and, through 
    the provision of an XSL stylesheet, a browser-based report describing the contents of a stud










SEND - test names greater than 40 characters

Sponsors may have test descriptions (--TEST) longer than 40 characters in their operational databases. Because the --TEST variable is meant to serve as a label for --TESTCD when a Findings dataset is transposed to a horizontal format, the length of --TEST is normally limited to 40 characters to conform to the limitations of the SAS v5 transport file format currently used for submission datasets. Therefore, sponsors have the choice to either insert the first 40 characters or a text string abbreviated to 40 characters in --TEST. To address this issue, sponsors may include the full description for these variables:

  • in the data definition file Origin column for --TEST, provide a link to the source containing the full test description; or
  • in a PDF document storing full-text descriptions. In such cases, in the data definition file Comments column for --TEST, insert a link to the full-text description in the PDF.
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