EAD Best Practices at the Library of Congress contains individually numbered sections (or "practices") arranged according to the order of EAD 2002 elements found in the Library's archival finding aids. Each LC practice includes required and optional sections.
The textual identifier for the practice. Usually an EAD element name.
Library of Congress Practice Number
An LC-assigned number for the practice. Practice numbers reflect the EAD element order recommended by LC's guidelines and the EAD 2002 DTD. This number is displayed before each practice name.
A brief summary of the practice, including information on relevant EAD elements and their use by the Library (e.g., required or recommended). Fuller EAD element descriptions are available in the EAD Tag Library.
Date the practice was last revised. Provides version control for the practice.
The predominant EAD elements discussed in the practice. EAD element names appear in angle brackets (for example, <acqinfo>).
References to related LC practices. Note: EAD Tag Library references are not found in this section but are documented elsewhere in a practice, where appropriate.
LC's recommended configurations for LABEL and HEAD attributes. LABEL provides consistent EAD displays across Library finding aids; HEAD helps both navigation and displays. An element (such as <did> subelements) may use the LABEL attribute or the element may include <head> as a subelement — both techniques, however, are never used for the same element.
LC's recommended MARC 21 configurations for the ENCODINGANALOG attribute (LC uses on only MARC 21 mappings in ENCODINGANALOG). Appendix A.3 of the EAD Tag Library provides a crosswalk between MARC 21 and EAD. Note that, while MARC indicators and subfields may be optionally be supplied for EAD elements, the cost of doing so must be weighed against probable utility and the ability to include such information accurately in a template. Therefore, LC:
- Provides specific MARC subfield(s) only when the element for which the encoding analog is given contains complete MARC subfield data (e.g., 260$c for <unitdate>).
- Does not list every MARC subfield in the element when the element contains an entire MARC field (e.g., 600 for <persname>).
- Includes MARC indicators only when necessary to distinguish among elements. For instance, the encoding analog for <relatedmaterial> is 544 1, and the encoding analog for <separatedmaterial> is 544 0.
In ENCODINGANALOG, LC uses a single space to separate a numeric MARC tag from its indicators and MARC indicators from subfields. The graphic symbol # identifies blank or undefined indicators, and the graphic symbol $ represents subfield delimiters. For example:
- encodinganalog="222 #3 $a"
(first indicator undefined; only one subfield)
- encodinganalog="245 04 $abc"
(both indicators have values; multiple subfields)
- encodinganalog="544 1# $3abcden"
(second indicator undefined; multiple subfields)
LC's recommended use and configuration of any relevant remaining attributes for EAD elements discussed in the practice. Note: the EAD Tag Library includes complete lists of all element attributes and their possible content, discussing each attribute at length in the "EAD Attributes" section. LC recommends:
- Setting the NORMAL attribute for both <date> and <unitdate>. LC date normalization follows ISO 8601 in YYYYMMDD format.
- Setting the SCRIPTCODE attribute for <language> within <langusage> and <langmaterial> using ISO 15924 only if non-Roman scripts need to be noted.
- Using as SOURCE attribute values in <controlaccess> the terms found in the semiclosed list from the EAD Tag Library (Version 1.0): aat, aacr2, cdwa, dot, gmgpc, lcnaf, lcsh, lctgm, local, mesh, mim, ncarules, nmc, rad, rbgenr, tgn, ulan.
Child elements for the broader parent EAD elements found in the practice. For example, elements used within the wrapper element <eadheader> are listed as subelements. Subelements are listed in LC-prescribed order and include information on whether the Library requires or recommends their use. When necessary, subelements may be decribed in a separate LC practice.
Illustrations of recommended LC markup for the practice. Each tagging example includes display examples that could be generated from the tagging markup, depending on output specifications. For clarity, display examples do not include formatting features (such as bold, italics, underlining, graphics, font, colors), although formatting is an essential component of EAD output stylesheets.
Additional recommendations and discussions related to LC's implementation of the practice.
A "yes/no" flag indicating whether an EAD element is repeatable. Also notes whether an element is recursive may be used within itself, e.g., <controlaccess> within a broader <controlaccess>).
LC's recommended order for EAD elements discussed in the practice. Includes order recommendations between elements ("following <userestrict> and preceding <altformavail>") as well as order within the parent element ("within <descgrp>").