National Information Exchange Model Conformance Specification
Version 3.0
August 15, 2014
NIEM Technical Architecture Committee (NTAC)

This document specifies general conformance guidance, principles, and rules for the National Information Exchange Model (NIEM) version 3.0.


This document is the specification for general NIEM conformance. It represents the collaborative work of the NIEM Business Architecture Committee (NBAC) and the NIEM Technical Architecture Committee (NTAC) and their predecessors.

This document is a product of the NIEM Program Management Office (PMO).

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1. Purpose

This is a high-level document that introduces NIEM conformance and provides a general normative definition for its meaning, how it applies, to what it applies, as well as to what it does not apply. This document describes the benefits of conformance, and refers to sources of information, tools, and help. See these references to learn more about NIEM conformance and how to apply NIEM conformance in practice.

Use this document to understand the general nature of NIEM conformance and to identify the key specifications that define the details of NIEM conformance for users and developers.

2. Definition of NIEM conformance

Conformance to NIEM is defined in terms of artifacts, NOT implementations, databases, systems, or tools. NIEM defines various conformance targets as the classes of artifacts to which sets of normative rules apply. This document will only address these concepts at a basic level. Refer to [NIEM NDR 3.0], [NIEM Conformance Targets Attribute Specification 3.0], and [NIEM MPD Specification 3.0] for more details on conformance targets.

[Definition: conformance target]

A class of artifact, such as an interface, protocol, document, platform, process or service that is the subject of conformance clauses and normative statements. There may be several conformance targets defined within a specification, and these targets may be diverse so as to reflect different aspects of a specification. For example, a protocol message and a protocol engine may be different conformance targets.

In general, the three most basic NIEM conformance targets are:

NIEM does not define information exchange implementation conformance. In general, an implementation that deploys NIEM-conformant instance XML documents on a transmission medium is considered a NIEM information exchange. However, an implementation may apply encryption, compression, Efficient XML Interchange (EXI) encoding [W3-EXI], or other security and/or efficiency techniques to an NIEM instance XML document as required; and it will still represent a NIEM information exchange. Furthermore, NIEM is considered a payload layer, and as such, a NIEM-conformant instance XML document may be contained within a standard envelope (such as SOAP, LEXS, etc.) or other XML-based standards. In describing an implementation that employs NIEM, an author should be as descriptive as is necessary to convey clear understanding of how NIEM is used.

Reference schema document sets (i.e., NIEM releases, domain updates, and core updates) are subject to rigorous quality and conformance testing to ensure they are NIEM-conformant. However, IEPDs are not under the NIEM PMO control and are not subject to a formal certification process (at this time). Therefore, it is important for NIEM users and developers to understand and make a concerted effort to ensure IEPDs they produce conform to the [NIEM MPD Specification 3.0].

In general, NIEM specifies that an IEPD conforms to NIEM under the following conditions:

  1. Each XML schema document within the IEPD adheres to all rules in the [NIEM NDR 3.0] for this schema’s conformance target class (e.g., reference schema document, extension schema document, external schema document, etc.).
  2. Each sample instance XML document within the IEPD validates to a NIEM-conformant schema document set in the IEPD, and adheres to all rules in the NIEM NDR for instance XML documents.
  3. The IEPD itself adheres to the NIEM MPD Specification (including required files, packaging, metadata, etc.).
  4. If an existing NIEM component matches the business semantics required by the IEPD, then that component is used by the IEPD, either directly or as the basis for derived components. That is, the IEPD does not unnecessarily duplicate NIEM components.
  5. Each NIEM schema component used by the IEPD, either directly or as the basis for derived components, is used in a manner consistent with the component’s structural definition and business semantics. That is, the IEPD preserves semantic and structural consistency.

There are subjective factors in applying these rules that require diligent consideration by the organization that develops an IEPD. It is important that decisions about semantics be made (or reviewed) by business subject-matter-experts (SMEs) who have thorough knowledge of the information exchange requirements, its business processes, and the domain for which it is being built.

For more detailed rules regarding IEPD conformance refer to [NIEM NDR 3.0] and [NIEM MPD Specification 3.0].

3. NIEM does not define compliance

NIEM does NOT define compliance. This term implies enforcement and the existence of an official certification process that verifies conformance or level of conformance. Though it is envisioned for NIEM in the future, a formal certification process does not yet exist. Therefore, compliance to NIEM is currently undefined and has no meaning.

Early in the development of NIEM (and its predecessor), governance committees discussed the language to be used in solicitations (such grants, RFPs, etc.) that require use of NIEM. They considered both terms, and concluded that the term compliance does not convey appropriate intent; it is too regulatory (for example, U.S. citizens and residents must comply with the U.S. tax code). The objectives of NIEM are to develop information exchange standards that users desire, but are not forced, to use. Furthermore, the purpose of both programs is to facilitate and support interoperability, NOT to force or regulate it.

Thus, the appropriate assertion is: Contract or grant awardees comply with contract or grant language, and that language requires IEPDs (and other MPDs), and their associated XML schema document sets and instance XML documents to conform to NIEM. (See [NIEM Implementation Guidance] which also outlines the general conformance rules.)

4. NIEM-aware or -supporting vs. NIEM-conformant

Systems, tools, and databases DO NOT and CANNOT conform to NIEM. Only XML schema documents and document sets, instance XML documents, and MPDs can conform to NIEM. For any other entity or artifact, NIEM conformance is undefined. Internal names, or usage of data, within a given system, tool, or database have absolutely no impact on the determination of NIEM conformance. Conformance is only about:

An XML schema document that copies, maps to, or uses the data component names of NIEM XML document schemas or the data components they contain without importing corresponding NIEM target namespaces does not conform to NIEM. Conforming to NIEM requires that an XML schema document reuse NIEM by importing through xs:import the target namespaces of NIEM reference schema documents or schema subset documents of NIEM reference schema documents.

A tool, system, or database may have capabilities designed to specifically support the development of NIEM-conformant IEPDs, or that may be part of a development environment that specifically supports the implementation of NIEM-conformant IEPDs, or that may be used to test or verify NIEM-conformance, etc. Also, a system may provide the capability to generate, send and receive, and/or process NIEM-conformant information exchanges. Such tools or systems are NOT considered NIEM-conformant, however, because they support conformance, they may be considered NIEM-aware or NIEM-supporting.

NIEM allows various extension methods to design and build additional XML data components that are not otherwise defined in NIEM. Tools that assist in the creation of such extensions may also be referred to as NIEM-aware or -supporting. However, implementers should be careful to avoid violating general conformance rules regarding duplication and consistency outlined above in Section 2, Definition of NIEM conformance, above.

5. Information sources for NIEM conformance

NIEM conformance means adherence to the following specifications:

Other useful non-normative documents and Web pages:

6. Benefits of IEPDs that conform to NIEM

There are several advantages to developing NIEM-conformant IEPDs, including:

7. Suggestions to IEPD developers

Obviously, being as knowledgeable as possible with XML, NIEM, and its documentation is important. To help increase understanding of and skill in building NIEM-conformant IEPDs, developers are also encouraged to:

Appendix A. References

[ISO-11179]: ISO/IEC STANDARD 11179: Information Technology - Metadata registries (MDR), an ISO/IEC multipart standard. NIEM uses these parts: Part 4 - Formulation of data definition (2004), Part 5 - Naming and identification principles (2005). Available from

[ISO-Schematron]: ISO/IEC STANDARD 19757-3: Information technology: Document Schema Definition Languages (DSDL) Part 3: Rule-based validation: Schematron. (1 Jun 2006). ISO/IEC. Retrieved from

[NIEM Conformance Targets Attribute Specification 3.0]: NIEM Conformance Targets Attribute Specification, Version 3.0, NIEM Technical Architecture Committee (NTAC), 31 July 2014. Available from

[NIEM NDR 3.0]: NIEM Naming and Design Rules, Version 3.0, NIEM Technical Architecture Committee (NTAC), 31 July 2014. Available from

[NIEM-HLTA]: NIEM High-Level Tool Architecture (HLTA), Version 1.1, NIEM Technical Architecture Committee (NTAC), 1 December 2008. Available from

[NIEM-HLVA]: NIEM High-Level Version Architecture, Version 1.0, NIEM Technical Architecture Committee (NTAC), 31 July 2008. Available from

[NIEM Implementation Guidance]: NIEM Implementation Guide, NIEM Program Management Office (PMO). Available from

[NIEM MPD Specification 3.0]: NIEM Model Package Description (MPD) Specification, Version 3.0, NIEM Technical Architecture Committee (NTAC), 15 August 2014. Available from

[NIEM-Tools]: NIEM Reference Tools, NIEM Program Management Office (PMO). Available from

[NIEM-Training]: NIEM Training, NIEM Program Management Office (PMO). Available from

[NIEM-UG]: NIEM User Guide, Volume 1, Bureau of Justice Assistance (BJA), 20 May 2008. Available from

[NIEM-UML]: NIEM-UML Profile, Version 1.0, Object Management Group (OMG), 1 June 2014. Available through

[W3-EXI]: Efficient XML Interchange (EXI) Format, v1.0, World Wide Web Consortium (W3C), 10 March 2011. Available from

[W3C XML Schema]: XML Schema Part 1: Structures Second Edition, W3C Recommendation 28 October 2004. Available from

XML Schema Part 2: Datatypes Second Edition, W3C Recommendation 28 October 2004. Available from

[XML-Validators]: XML Schema validator examples: XSV, XERCES, Saxon

[NIEM-Tools-Catalog]: NIEM Tools Catalog, NIEM Program Management Office (PMO). Available from