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Metadata Authority Description Schema (MADS): Official Web Site

MADS User Guidelines (ver. 2.0) » Introduction and Implementation

Introduction and Implementation

The Metadata Authority Description Schema (MADS) is an XML schema for an authority element set that may be used to provide metadata about authorized forms of agents (e.g., people, organizations), events (e.g., conferences, meetings), and terms (e.g., topics, geographics, genres). MADS serves as a companion to the Metadata Object Description Schema (MODS) to provide metadata about the authoritative entities used in MODS descriptions. The standard is maintained by the MODS/MADS Editorial Committee with the Network Development and MARC Standards Office of the Library of Congress and input from users.

XML Structures

MADS is expressed using the XML (Extensible Markup Language) schema language of the World Wide Web Consortium. XML provides markup for documents and allows more flexibility and detail than HTML (Hypertext Markup Language). It serves well as a syntax for metadata.

By using the XML schema language, MADS defines main elements, child elements (i.e., subelements), and attributes of elements and subelements. Data content is included in the lowest level elements so as to avoid "mixed content," which is when some elements contain character data interspersed with child elements. Thus, some elements are only "containers"; a "container" element is one that it used to bind together subelements, but contains no data other than tags.

Attributes may be associated with elements at any level and are defined with the element with which they are associated. They serve to modify the element. Attributes are not in a mandated sequence and are not repeatable (per XML rules). There are some common Attributes Used Throughout the MADS schema that have the same use and meaning with any element or subelement for which they are defined.

A MADS document contains a schema declaration that indicates the MADS namespace:


An "XSLT stylesheet" (Extensible Stylesheet Language Transformation) may be written to transform the MADS data in some way for output. Examples include using a stylesheet to place the record into a template with easy-to-understand element names in XML; using a stylesheet to transform a MARC 21 authority record to MADS; or using a stylesheet to transform coded data into textual form.

MADS Record Structure

MADS Root Elements

Each individual MADS record is contained within the <mads> root element.

A MADS Collection is a group of MADS records that are contained within the <madsCollection> root element.

MADS Top Level Core Elements

A MADS record (the elements within the <mads> tags) is made up of the following parts:

  • Authoritative Heading Label – consists of one or more <authority> elements. The <authority> element has one or more descriptors (subelements): <name>, <titleInfo>, <topic>, <temporal>, <genre>, <geographic>, <hierarchicalGeographic>, and/or <occupation>. There may be any combination of these descriptors in any order. The <authority> element is repeated only if needed to give multiple authoritative forms in different languages or scripts.
  • Variant Heading Label – contains references to variant forms of the authoritative heading label. The <variant> element includes one or more names or terms (i.e. descriptors as above) that are alternate forms of the authoritative heading but are not considered the authoritative form. For example, if the person's authoritative name is John J. Jones, but he is sometimes referred to as J.J. Jones, then J.J. Jones is referenced under <variant>. In library catalogs the variant heading is equivalent to a "see" reference and is not used in the bibliographic metadata; the variant form leads users to the correct authoritative label form. A special relationship between the variant and the authoritative heading may be expressed in the type attribute of the <variant> element.
  • Related Heading Label – contains references to other related authority records. The <related> element includes one or more names or terms (i.e., descriptors as above) that have some relation to the authoritative heading and is a legitimate, authoritative heading of its own. The <related> element is equivalent to a "see also" reference in a library catalog. The relationship between the related and the authoritative heading may be expressed in the type attribute of the <related> element.

There may be any number of <variant> and/or <related> elements in a MADS record. Both of these elements are composed of the same descriptors (subelements) as used under <authority>.

MADS Other Top Level Elements

The following additional elements have been defined to provide additional information about the authoritative heading or the entity that it represents:

The following element provides administrative information about the record and its metadata rather than about the <authority> itself:

Implementation Notes

Cataloging Rules

Any set of cataloging rules may be used with MADS, as is the case with MODS and MARC 21.


If using International Standard Bibliographic Description (ISBD) or other punctuation in creating MADS records, punctuation should be retained if it occurs within an element, but should be dropped between elements. If desired, an XSLT stylesheet may be used to generate an ISBD or other eye-readable display from the MADS elements and data, for instance the dash used in LCSH headings between facets.


MADS metadata:

<topic>Academic libraries</topic>

User readable Display after XSLT transformation:

Academic libraries--Automation--Bibliography

MADS Record Identifier

It is expected that a MADS record would have its own unique ID in addition to any other identifiers associated with the authority (which are indicated under <identifier>). The MADS record identifier is indicated in <recordInfo><recordIdentifier>.

Root Elements

All MADS elements are declared as global. This allows them to be used as root elements for instance documents, or imported into other schemas.

Mandatory Elements

The root element <mads> is mandatory. The version of MADS used may be specified with the version attribute. In version 2.0 the value "2.0" is enumerated in the schema, and thus should be used as the value if the version attribute is included.

At least one main element <authority> and at least one subelement under <authority> are mandatory.

It is recommended, although not required, to have the <recordInfo> element.

Some optional elements, if used, have mandatory subelements. See the individual element descriptions for further information. Profiles may be developed for specific applications, as needed, to specify other mandatory elements.

Order of Elements

The order of elements in the MADS schema does not assume display order. A stylesheet is used to control the display order of MADS records.

Element Repeatability

All MADS top level elements are repeatable.

Relationship between MADS and MARC 21 Elements

Most MADS elements have equivalent fields in the MARC 21 Authority Format. However, since MADS has fewer data elements than MARC authorities, records converted from MARC to MADS that are then converted back to MARC will lose some data or specificity of tagging. Where there is no equivalent MARC 21 element, the mapping section of the individual element description says: "There is no MARC 21 Authority field equivalent."

Each element and subelement description in this User Guide includes a MARC Mapping section that gives the general equivalencies between the MARC 21 Authority Format and MADS, but this is not intended to be a crosswalk that allows for bi-directional conversions without some loss of data. There is a separate mapping document.

For a summary listing of all the mappings, see the MARC 21 Authority Format Mapping to MADS Schema version 2.0.

The Library of Congress' Network Development and MARC Standards Office has developed a framework for working with MARC data in an XML environment. See the MARCXML webpage for more information.


Last Updated: April 5, 2012