CDASH and SDTM are each optimized for different purposes, and the philosophy behind each drives the design. SDTM represents cleaned, final CRF data organized in a predictable format that facilitates data transmission, review and reuse. CDASH collects the data in a user-friendly, EDC/CRF-friendly way that maximizes data quality and flows smoothly into SDTM.
CDISC employs a rigorous approach to developing data standards. Each standard is informed and shaped by experts, making them not just of the highest quality, but also attuned to the practicalities of their implementation.
On occasion the mapping from CDASH to SDTM is complex. This article provides a step-by-step explanation to help follow the iteration from the CDASH example to the SDTM example.
The QNAM values that appear in various examples published in the SDTMIG and TAUGs have sometimes included the domain code, and sometimes not.
In SDTMIG v3.4 and SDTM v2.0, formats for Date/Time variables are now specified as "ISO 8601 datetime or interval." You may ask “What's that interval format and when would I use it?”