What this test checks
This test checks whether the PDF document uses header tags consistently and doesn't skip header levels.
Why this maybe a barrier
Headers provide an easy navigation structure for readers using assistive technologies and can be used for quick comprehension. Many users especially those using assistive technologies use headers as way to navigate the document to reach relevant content quickly.
Inconsistent use of headers can cause barriers with assistive technologies in navigating the document and following the document structure correctly.
WCAG 2.2 Technique
This check is related to the WCAG 2.2 technique → PDF9: Providing headings by marking content with heading tags in PDF documents.
WCAG 2.2 Success Criteria
This test is related to multiple WCAG success criteria:
1.3.1 Info and Relationships (Level A) — "Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text."
For more information, visit WCAG 2.2 Success Criteria 1.3.1, under the guideline Adaptable.
2.4.1 Bypass Blocks (Level A) — "A mechanism is available to bypass blocks of content that are repeated on multiple Web pages."
For more information visit, WCAG 2.2 Success Criteria 2.4.1, under the guideline Navigable.
PDF/UA Principle
Section 7.4: Headings — This section lays down the requirement for "Numbered Headings". For implementation, the test uses the following Matterhorn protocol checkpoints namely:
- 14-001 — Headings are not tagged.
- 14-002 — Does use numbered headings, but the first heading tag is not <H1>.
- 14-003 — Numbered heading levels in descending sequence are skipped, for example
<H3>follows<H1>.