100K-Site Overlay Effectiveness Study

The Grow Wild Agency 100K-Site Overlay Effectiveness Study evaluates whether installed accessibility overlay widgets correlate with reduced WCAG 2.1 AA failures across a 100,000-site sample. The study cross-references presence of an overlay against detected WCAG failures, against the WebAIM Big Six baseline, and against ADA Title III federal lawsuit status from EcomBack 2025 data.

Methodology

  1. Sample frame: Top 100,000 sites by Tranco rank (Sept 2025 snapshot).
  2. Overlay detection: Heuristic match against the script signatures of the 10 largest commercial overlay vendors (accessiBe, UserWay, EqualWeb, AudioEye, Recite Me, AccessiWay, etc.).
  3. WCAG scanning: axe-core core ruleset, plus the WebAIM Million 2026 ruleset applied to the home page; 7 of the 8 most-common failure types instrumented.
  4. Lawsuit cross-reference: Domain match against EcomBack 2025 H1 and H2 federal-filing lists (where domain identification is publicly available).
  5. Control: matched-pair comparison of overlay-installed sites against same-industry, same-size non-overlay sites.

Headline findings

  • Overlay-installed sites do not show a statistically significant reduction in the WebAIM Big Six failure rates relative to matched controls.
  • Overlay-installed sites are over-represented among 2025 ADA federal lawsuit defendants — consistent with EcomBack's 22.64% figure for H1 2025.
  • Overlay-injected ARIA frequently introduces secondary failures (invalid role/state combinations, focus traps) detected as new findings on rescan.
  • Conclusion: installing an overlay does not reduce ADA litigation risk and may increase it by creating a false sense of compliance.

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