Check NDR Conformance Using Schematron Validation

ConTesA is a free web tool provided by the NIEM program that also may be used to check NDR conformance.


Download the NDR schematron rules. These are available in the NDR zip file and on the NDR GitHub repo.

Schematron files have a .sch file extension.

The Schematron file(s) will be needed each time you test NDR conformance. The two key files for this task are:

  • ndr-rules-conformance-target-ext.sch - Schematron rules for EXT schemas
  • ndr-rules-conformance-target-ref.sch - Schematron rules for REF schemas

Schematron Validation

  • In Oxygen, open the NIEM XML schema to test for NDR conformance. This might be an IEPD extension schema or a NIEM domain schema under development.

  • Open the “Validate with…” dialog box. There are three different ways of doing this:

    • (Option 1) From the menu bar, click on Document > Validate > Validate with…

    • (Option 2) Click the drop-down on the Validate (check mark) button and select Validate with..., as shown below.

      Validate With Icon

    • (Option 3) From an open Oxygen project, right-click on one or more selected schema files or folders, as shown below.

      Project schema right-click to Validate With

  • In the Validate with dialog box…

    • Change the Schema Type field from XML Schema to Schematron.

      Change Schema type

    • In the URL field, browse to the downloaded Schematron file. Make sure to choose the appropriate file (REF or EXT) for your NIEM schema.

      • IEPD extension schemas typically use EXT rules.
      • Domain schemas use REF rules.

      URL field

    • Click OK to run the conformance validation.

Review Conformance Errors

Conformance errors and warnings will appear in the Results panel.

  • The NDR rule number appears, along with the rule title, so that the NDR may be easily referenced for more information about the rule.
  • Double-click on an error or warning to jump to that line in the schema.

The image below shows several modifications to a local copy of Core in order to demonstrate errors:

Conformance Errors

After making corrections, rerun the steps above to test conformance on the updated schema.

Please see Oxygen’s video for more information about Schematron validation in Oxygen.