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Accessibility Benchmarking

What is accessibility benchmarking and how do you compare compliance across sites?

By eiSEO Team · Published Mar 3, 2026

What is accessibility benchmarking?

Accessibility benchmarking is the practice of measuring and comparing WCAG compliance metrics across multiple websites to establish baselines, track progress, and identify competitive gaps. Rather than auditing a single site in isolation, benchmarking uses normalized metrics like errors per page and health scores to make fair comparisons between sites of different sizes. A site with 50 accessibility errors across 500 pages (0.1 errors/page) is performing better than one with 20 errors across 10 pages (2.0 errors/page).

Accessibility benchmarking is the practice of comparing WCAG compliance metrics across multiple websites using normalized measures like errors per page and health scores, enabling fair comparisons regardless of site size and establishing baselines for tracking remediation progress.

Why does accessibility benchmarking matter?

Raw error counts are misleading without context. A large e-commerce site will naturally surface more issues than a 5-page brochure site, but that does not mean it is less accessible. Benchmarking normalizes these numbers so teams can set realistic targets, prioritize fixes against industry peers, and demonstrate measurable improvement to stakeholders. Organizations that benchmark accessibility see faster remediation because the data creates clear, comparable goals.

Key statistics

96.3% of home pages had detected WCAG 2 failures, with an average of 56.8 errors per page across the top 1 million websites.

Source: WebAIM Million

Organizations that track accessibility metrics over time remediate issues 60% faster than those that perform only one-time audits.

Source: Deque Systems

How to fix it

  1. 1

    Run accessibility scans (using axe-core or similar tools) across your own sites and key competitor sites to collect baseline error counts, warning counts, and pages scanned.

  2. 2

    Calculate errors per page (total errors divided by pages scanned) to normalize for site size differences when comparing results.

  3. 3

    Compute a health score using the formula: 100 minus 3 points per error-per-page minus 1 point per warning-per-page, clamped between 0 and 100.

  4. 4

    Break down issues by severity — critical and high severity issues are counted as errors, medium as warnings, and low as informational — to prioritize the most impactful fixes.

  5. 5

    Track scores over time by running repeated scans and comparing results to confirm that fixes are reducing your error rate rather than just shifting issues between categories.

Code example

Bad 
<!-- Reporting only raw counts --><p>Site A: 150 errors. Site B: 30 errors.</p><!-- Misleading: Site A has 5,000 pages, Site B has 10 pages -->
Good 
<!-- Normalized comparison --><table><tr><th>Site</th><th>Errors</th><th>Pages</th><th>Errors/Page</th><th>Score</th></tr><tr><td>Site A</td><td>150</td><td>5000</td><td>0.03</td><td>99</td></tr><tr><td>Site B</td><td>30</td><td>10</td><td>3.0</td><td>91</td></tr></table>

Frequently asked questions

A 5,000-page site will naturally surface more total errors than a 10-page site, even if the larger site is better maintained. Normalizing by pages scanned (errors per page) gives a fair comparison regardless of site size.
The health score starts at 100, subtracts 3 points for each error per page and 1 point for each warning per page, and is clamped between 0 and 100. A score of 80 or above is considered good, 50-79 needs attention, and below 50 is critical.
Run benchmarking scans at least monthly, or after every major site update or content deployment. Tracking trends over the last 5 scans reveals whether your remediation efforts are working or if new issues are being introduced faster than old ones are fixed.

Related topics

Critical

Color Contrast

Color contrast is the difference in luminance between foreground text and its background. WCAG 2.1 requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text (18px bold or 24px regular). Insufficient contrast makes content difficult or impossible to read for users with low vision, color blindness, or those viewing screens in bright sunlight.

Read more →
High

ARIA Violations

ARIA (Accessible Rich Internet Applications) attributes provide extra semantic information to assistive technologies when native HTML elements are insufficient. ARIA violations occur when these attributes are used incorrectly — for example, applying an invalid role, using aria-labelledby to reference a non-existent ID, or adding redundant ARIA roles to elements that already have implicit semantics.

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Critical

Image Alt Text

Alt text (the HTML alt attribute) is a short text description of an image that screen readers announce to visually impaired users. It also displays when an image fails to load and is used by search engines to understand image content. Every non-decorative image on a page must have meaningful alt text that conveys the image's purpose or information.

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