Schematron in ODD

In an ODD, Schematron rules, assertions, or reports can appear in a constraintSpec scheme="isoschematron" which itself can appear in attDef, classSpec, elementSpec, or schemaSpec

If the sch:rule is missing (i.e., just bare sch:assert and sch:report elements), then the context is the element or attribute that is being defined.

In an ODD, you need to specify the tei: prefix for TEI elements!

XPath and Schematron for TEI Customization, slide 23 of 24