JATS does not actually claim to be a "one size fits all" specification. However, many information content consumers (libraries, archives, on-line services) accept only content that is valid to one of the JATS models, and in many cases specify a subset of the model defined in one of the JATS instantiations (Archiving, Publishing, or Authoring). Thus, content creators find that their vendors and tools often assume that they will be using one of the JATS models "out of the box". This can present a real problem when a publisher has, and wants, information that is not modeled in JATS, or is not modeled in the JATS DTD their vendors and publishing partners require. In this case, the publisher has several options: Drop the inconvenient information; use "Custom Metadata" , hide the inconvenient information in prose, abuse a tag, suggest a modification of the standard, or modify the tag set to encode the information that matters to you. None of these options are ideal, and which to choose in large part depends on circumstances.