Validation

edc-cdisc bundles the official CDISC ODM 1.3.1 XSD schema and provides validate_odm to check a document against it.

from edc_cdisc import validate_odm

problems = validate_odm(xml)   # xml: bytes or an lxml element
if problems:
    for p in problems:
        print(p)
else:
    print("valid")

validate_odm returns a list of problem strings — an empty list means the document is both schema-valid and internally consistent. It performs two checks:

1. XSD validation against the bundled ODM 1.3.1 schema. Failures are reported as "XSD line <n>: <message>".

2. Reference integrity — every OID reference (StudyOID, MetaDataVersionOID, StudyEventOID, FormOID, ItemGroupOID, ItemOID, CodeListOID) must point at a defined OID. A dangling reference is reported as "dangling ref: <oid>".

Which documents to validate

Reference integrity only holds within a self-contained document:

• Metadata (MetadataSerializer) — internal refs (Protocol → StudyEventDef, ItemGroupDef → ItemDef …) resolve → expect [].

• Combined snapshot (SnapshotSerializer) — the data refs resolve against the metadata in the same file → expect []. This is the most thorough check.

• Clinical data alone (ClinicalDataSerializer) — its StudyEventOID / FormOID references point at definitions that live in the separate metadata file, so they will show as dangling ref here. That is expected; assert only that there are no XSD problems.

problems = validate_odm(clinical_xml)
assert [p for p in problems if p.startswith("XSD")] == []

What XSD validation does not catch

The ODM schema does not express OID cross-references as xs:keyref, so XSD alone will not flag a dangling reference — that is exactly why validate_odm adds the reference-integrity pass. It also does not flag orphan definitions (a def that no ref points at); the reference check is refs - defs, not the reverse.

Bundled schema

The XSD files ship inside the package at edc_cdisc/odm_schema/ (from the NCI EVS CDISC repository), so validate_odm works both from a source checkout and from an installed wheel.