Error guide

Invalid document structure in JATS XML

The invalid document structure error refers to problems in the global architecture of a JATS article, not a single misplaced element. It typically indicates missing mandatory blocks, incorrect order, or mixing incompatible JATS profiles.

This type of error prevents the article from passing even basic JATS validation, which in turn blocks progress toward indexing in SciELO, PMC, or other repositories: none of them process a document whose front/body/back architecture is not recognizable.

Correct anatomy of a JATS article

A valid JATS document—regardless of Tag Set (Archiving, Journal Publishing, or Article Authoring)—organizes content in three main regions within <article>:

<article xmlns:xlink="http://www.w3.org/1999/xlink"
         article-type="research-article"
         dtd-version="1.4">
  <front>
    <journal-meta>...</journal-meta>
    <article-meta>...</article-meta>
  </front>
  <body>
    <sec>...</sec>
  </body>
  <back>
    <ref-list>...</ref-list>
  </back>
</article>

Block	Content
`<front>`	Journal and article metadata
`<body>`	Main text, figures, tables
`<back>`	References, acknowledgments, notes

Frequent structural errors

1. Missing `<front>` block

Symptom: Metadata loose outside <front> or directly under <article>.

Incorrect:

<article article-type="research-article" dtd-version="1.4">
  <article-meta>
    <title-group>
      <article-title>Title</article-title>
    </title-group>
  </article-meta>
  <body>...</body>
</article>

Correct:

<article article-type="research-article" dtd-version="1.4">
  <front>
    <journal-meta>...</journal-meta>
    <article-meta>
      <title-group>
        <article-title>Title</article-title>
      </title-group>
    </article-meta>
  </front>
  <body>...</body>
</article>

2. References inside body

Bibliographic citations belong in <back>, not at the end of <body>.

Incorrect:

<body>
  <sec><title>Discussion</title><p>...</p></sec>
  <ref-list>...</ref-list>
</body>

Correct:

<body>
  <sec><title>Discussion</title><p>...</p></sec>
</body>
<back>
  <ref-list>...</ref-list>
</back>

3. Incorrect block order

JATS requires the order front → body → back. Placing <back> before <body> generates a structural error.

4. Missing `<journal-meta>`

Although some workflows omit journal metadata in individual articles, SciELO SPS and most indexers require it within <front>.

<front>
  <journal-meta>
    <issn pub-type="epub">1234-5678</issn>
    <journal-title-group>
      <journal-title>Scientific Journal</journal-title>
    </journal-title-group>
  </journal-meta>
  <article-meta>...</article-meta>
</front>

Difference between well-formed and valid structure

Well-formed XML parses without syntax errors (closed tags, single root). Structurally valid XML also complies with JATS hierarchy. XML can be well-formed and fail structure:

Missing XML declaration or incorrect encoding (UTF-8 recommended).
Multiple root elements.
Missing mandatory blocks.

Validate both levels in the JATS validator.

Systematic diagnosis

Confirm a single root element <article>.
Verify presence of <front>, <body>, and <back>.
Confirm <journal-meta> and <article-meta> inside <front>.
Move <ref-list> to <back> if elsewhere.
Review order of the three main blocks.
Revalidate and address secondary errors such as element not allowed.

Prevention

Use templates with complete predefined structure.
Do not allow authors to edit XML without automatic validation.
Document variations by article-type (editorials may have minimal body).
Consult the complete JATS XML guide as an architecture reference.

For journals without XML experience, JATS XML production ensures compliant structure from the first issue.

Conclusion

Invalid document structure is an architecture error, not a detail error. Correcting the front/body/back hierarchy resolves the foundation on which all other metadata and content depend. Once global structure is aligned, remaining errors usually drop dramatically.

Validate your article in the JATS validator and see common JATS errors for the full picture.