SDTM mapping is pattern-matching with consequences

SDTM mapping transforms clinical trial data into the standardized tabular structure the FDA expects in a submission package. A submission package with non-conforming SDTM can fail Pinnacle 21 validation — triggering a deficiency letter that adds months to review time.

LLMs are very good at the majority case: standard CRF fields that map cleanly to well-documented SDTM domains. LLMs are also good at recognizing controlled terminology matches. The failure modes cluster around novelty, sponsor-specific conventions, derived variables, and cross-domain consistency.