<subject> Subject Name

Name of one overarching category, broad classification, topic, or theme used to describe a standards document, as a higher-level descriptor of its content.


In JATS (the specification on which NISO STS was based), subjects are used to organize articles in a Table of Contents or similar. In standards documents, subjects have been used to organize standards into series or provide category classing. The source of the subjects can be a classification scheme, such as a taxonomy (ISO STD 25964:-1:ed-1:2011 https://www.iso.org/obp/ui/#iso:std:iso:25964:-1:ed-1:v1:en:term:2.6).
Language in Subjects
Subject elements are contained in <subj-group> elements. There may be several <subj-group>s, each of which can be identified separately by language, vocabulary, or taxonomy source. None of the individual subject elements (<subject> and <compound-subject>) take the @xml:lang attribute; that is reserved for the group level (<subj-group>). This means that if there are keywords in several languages they should be in different <kwd-group>s.
Vocabulary Attributes
For controlled vocabularies, two attributes can be used to link a subject term to its source:
  • @vocab-term — This attribute holds the canonical form of the subject term as expressed in the vocabulary named on the <subj-group> element. The content of the subject element (<subject> or <compound-subject>) might not be exactly the same as the canonical form, as the <subject> content might be a user-specific variant.
  • @vocab-term-identifier — This attribute holds a unique identifier and possible pointer to the specific subject term in the named vocabulary. While this is typically a URI or DOI reference, the @vocab-term-identifier could be an item number or other system-specific identifier.
Related Elements
Types of Subjects: This Tag Set contains several differently-structured types of subject elements:
  • <subject> is used with simple subjects: words or phrases.
  • <compound-subject> is used with multi-part subjects, such as a subjects that contains both a code and its description/name/title.
  • <ics>Used to hold ICS terms, which are a special kind of subjects that are not tagged as <subject>s, but rather use their own specific elements (<ics-wrap>, <ics>, and <ics-desc>).
Keywords vs Subjects Terms: Subject terms (collected within a <subj-group> element) name broad classifications, categories, topics, or themes that describe or classify a standard. Keywords (collected within a <kwd-group> element) contain words from the narrative text or words (such as broader and narrower terms) related to that text.

Base Attributes

Models and Context
May be contained in
Content Model
<!ELEMENT  subject      (#PCDATA %subject-elements;)*                >
Expanded Content Model

(#PCDATA | bold | fixed-case | italic | monospace | num | overline | roman | sans-serif | sc | strike | underline | ruby | alternatives | inline-graphic | private-char | chem-struct | inline-formula | named-content | styled-content | sub | sup)*

Tagged Samples
Subjects from SDO-specific taxonomy showing vocabulary attributes
<subj-group id="SG1.1" originator="ASME" vocab="ASME-Taxonomy"
  xml:lang="en" subj-group-type="Industries"
 <subject id="SG1.1-1"
  >Fossil Power</subject>
 <subject id="SG1.1-2"
  >Power Plants</subject>

<subj-group id="SG1.2" originator="ASME" vocab="ASME-Taxonomy"
  xml:lang="en" subj-group-type="Materials-Product-Form"
 <subject id="SG1.2-1"
 <subject id="SG1.2-2"
  >Pressure Vessels</subject>
Subject from Dewey Decimal showing canonical term in @vocab-term attribute and its translation in subject content (Note “Engineering of railroads, roads” is DDC term, not free text.)
<subj-group id="DDC-ex1" vocab="DDC" vocab-identifier="DDC23" xml:lang="en">
 <subject id="DCC-625" vocab-term="Engineering of railroads, roads"
  Ingénierie des chemins de fer, routes</subject>