NIEM Information Exchange Package Documentation (IEPD) Specification

The NIEM Information Exchange Package Documentation (IEPD) Specification specifies normative rules and non-normative guidance for building NIEM information exchange messages.

This specification was previously known as the NIEM Model Package Description (MPD) Specification. For 5.0, the MPD specification was simplified to focus specifically on IEPDs (one of the specialized kinds of model packages) and renamed.


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Available versions

Conformance Targets

The IEPD Specification includes the following conformance targets:

ID Code Conformance Target Description Spec
IEPD Information Exchange Package Documentation A set of artifacts that define the content, structure, and meaning of an information exchange message. The schemas contained by the IEPD must conform to the NIEM Naming and Design Rules (NDR). Link
WF-IEPD Well-formed IEPD An IEPD with a less-strict set of requirements. A well-formed IEPD focuses on the format and structure of the package, includes a valid IEPD catalog with no broken links, and includes and uses other general IEPD artifacts correctly; however, schema conformance to the NIEM Naming and Design Rules (NDR) is not required. Link
IEP Information Exchange Package An information exchange message, as an XML instance document. The use of NIEM-defined elements is not required. Link
FN-IEP Full NIEM IEP An information exchange message, as an XML instance document. Ths use of elements defined by NIEM reference or extension schemas is required. Link
Schema-subset Schema document subset A set of schemas, corresponding to a set of full reference schemas, that have been reduced and constrained to include only the files and components needed for an information exchange. Link
IEPD-catalog IEPD catalog document A XML file that contains metadata about the IEPD, including descriptive information and an index of the files it contains. Link
XML-catalog XML catalog document A XML file that maps namespaces to file locations. Link


The IEPD Specification describes the following artifacts:

Schema Artifacts

Artifact Description
Reference Schema Document A NIEM schema that represents the full authoritative schema document for its target namespace.
Subset Document Schema  
Extension Schema Document  
External Schema Document A schema included in an IEPD that does not conform to NIEM. Content from external schemas must be accessed via NIEM adapters.
Constraint-Schema Document Set A set of schemas that define additional constraints outside of what is permitted in a regular NIEM-conformant schema. Used as second-pass validation for IEPs (IEPs must first validate to the original reference or subset schemas).

Required Document Artifacts

Artifact Description
IEPD Catalog  
Change Log An artifacts that describes the changes applies to an IEPD since its previous version.
ReadMe The initial source of human-readable information about the IEPD.
XML Catalog An XML catalog is a XML document that assigns locations to files. This can be used to override the file locations assigned by NIEM XML schema import statements without having to modify the original schema itself.
Sample instances A sample instance is an example of the message, with actual or example data. These can be very helpful for implementers of the IEPD.
Conformance Report / Assertion  

Optional Artifacts

Aside from the required artifacts, IEPD content is relatively flexible. A variety of other optional documentation files may be incorporated into an IEPD. When applicable, these may include (but are not limited to) files that describe or explain:

  • Implementation details (hardware, software, configuration, etc.)
  • Use of multiple root elements
  • Use of multiple subsets or mixed releases
  • How to use/reuse an IEPD for various purposes (such as Web Services)
  • Rationales and/or business purposes
Artifact Description
NIEM Wantlist A wantlist is an abbreviated XML representation of a NIEM schema document subset, and identifies only the data components a user selected to build a schema document subset. A wantlist file is required to be able to reload a NIEM subset into the SSGT for future editing.
Business Rules Business rules constrain a message. They may be written as descriptive text or in a language that enables validation, such as Schematron.

Packaging a IEPD

The IEPD Specification does not contain normative rules on how to structure the folders and place the files in an IEPD, but guidance is provided. A recommended layout is provided below:

See Appendix E. Guidance for IEPD Directories (non-normative) from the IEPD Specification for more information and helpful tips on how to organize an IEPD.




    niem/               # NIEM subset schemas


      ic-ism/           # Example external standard


  documentation/        # Human-readable documentation