External Identifier: The <issue-id> element holds an external identifier, typically assigned to an article by a publisher. The contents of this element should not be confused with the @id attribute, which holds an internal document identifier that can be used by software to preform a simple link inside the document.

Type of Identifier Best Practice: Best Practice is to use the @pub-id-type attribute to indicate the type of the external identifier, such as a publisher’s identifier, a DOI, a PMID, an aggregator’s or archive’s identifier, the identifier assigned by an indexing or hosting service, or similar. (See @pub-id-type for values.)

Authority for Identifier Best Practice: The attribute @assigning-authority should name the organization or system that assigned the identifier or administers the identifier (such as Crossref, OCLC, GenBank, Figshare).

Historical Note: Until JATS version 1.2d2 (2018), the @pub-id-type’s value conflated two meanings: the attribute could hold the type of identifier (such as a DOI or ISBN), or it could hold the name of the organization or system that defined or registered the identifier (such as Crossref). There was no way to state both that the identifier content of the element was a DOI and that the server was Figshare or Crossref. Although all the previous @pub-id-type values will continue to be accepted, for Best Practice, the @assigning-authority should name an organization and the @pub-id-type attribute should describe the identifier type.