Headings are out of order
49.3%
of the 609 sites we scanned fail this
Ranging from 25.2% of EU e-commerce to 69.7% of US healthcare providers. Pooled across five targeted cohorts, so treat it as a convenience sample rather than a rate for the web.
What it means and how to fix it
Users navigating by headings may lose context when heading levels are skipped or appear out of order.
The fix. Keep headings in sequence without skipping levels; use styling for size, not heading level.
What it looks like in code
HTML<h4 id="...">
<a href="/path" target="_self">Text</a>
</h4><h1>Page title</h1>
<h2>Section</h2>
<h3>Subsection</h3>Heading levels must not skip. Jumping h2 to h4 implies a missing section, which misleads anyone navigating by heading structure.
The failing example is real markup from a site in our research cohorts. Class, style and data attributes are removed, and ... marks a value we elided. The structure is unchanged, because the structure is the failure.
How often it fails
Share of scanned sites in each cohort. These are five targeted studies, not a random sample of the web, so read the contrast between cohorts rather than any one figure as a web-wide rate.
Who fails it most3 cuts by state, CMS vendor, sector
By state
By CMS vendor
By sector
Groups smaller than 8 sites are not shown: a rate over a handful of sites moves by tens of points on a single result.
What this does not measureLimits of these figures, and where the corpus came from
- This rule maps to no success criterion, so a site failing it is not failing WCAG. It is still worth fixing: these are the patterns that decide whether assistive technology can navigate a page efficiently rather than merely read it.
- These are five targeted cohorts, not a random sample of the web. Per-cohort rates are the figure to quote; the pooled rate is a convenience sample.
- Denominators count sites that produced a result. Sites that were blocked or errored are excluded rather than counted as passing.
- Occurrence counts are floors: the engine records at most 25 occurrences of a rule per page.
- The EU and Indian cohorts retained only the primary success criterion per finding, so a rule mapping to several criteria contributes to one of them in those two cohorts and to all of them in the other three.
| Cohort | Scanned | Attempted |
|---|---|---|
| Shopify DTC stores | 75 | 75 |
| US local government | 158 | 221 |
| US healthcare providers | 208 | 218 |
| EU e-commerce | 107 | 170 |
| Indian financial services | 61 | 72 |
Corpus generated 2026-09-18.
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