Web Accessibility as a Side Effect
John T. Richards, Kyle Montague, Vicki L. Hanson · 2012 · Proceedings of the 14th International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS 2012) · doi:10.1145/2384916.2384931
Summary
This paper investigates the conjecture that improvements in web accessibility have arisen partly as unintentional side effects of changes in web technology and design practices, rather than from deliberate accessibility efforts. Building on a prior 14-year longitudinal study (1999-2012) of 1,174 high-traffic and government webpages that found growing adherence to some accessibility criteria, the authors examine three specific web technology trends that may have incidentally improved accessibility: (1) the adoption of CSS for layout replacing table-based designs and image splicing, which made pages more parseable by assistive technology and easier for users to customize; (2) the growing attention to search engine optimization (SEO), which incentivized practices like descriptive page titles, alt text, semantic headings, and link titles that also benefit screen reader users; and (3) the shift toward cross-device content design driven by mobile devices, which encouraged fluid sizing, content modularization, and page linearization — all beneficial for accessibility. The research combined automated analysis of the full corpus with detailed manual inspection of four representative websites (two government, one news, one e-commerce) tracked over the full 14-year period.
Key findings
The data reveals striking trends. Heading usage grew from 7.5% of top sites in 1999 to 86.4% by 2012, with heading structure becoming deeper and more meaningful over time (H1 decreasing from 25% to 6.6% of all headings while H2 grew from 6.3% to 41.9%). Decorative images decreased dramatically while clean CSS-only layouts increased. Use of title attributes on links grew from nearly zero to 9.5-15.2% by 2012, though manual inspection revealed these were often populated with redundant text. Alt text for content images showed moderate linear improvement, reaching 44% on top sites and 62% on government sites by 2012. However, the manual inspection revealed important nuances: while sites increasingly declared XHTML doctypes, many continued producing non-compliant HTML markup; heading tags were sometimes used for SEO rather than semantic structure (e.g., using H2 and H4 tags on product listings for search indexing); and the shift from using characters for letter-spacing to CSS letter-spacing eliminated a practice that caused screen readers to read words as individual characters. The move from fixed pixel sizing to ems and percentages for cross-device support also improved the ability of adaptation software to resize content for low vision users.
Relevance
This paper offers a paradigm-shifting perspective for accessibility advocates: rather than relying solely on guidelines compliance and awareness campaigns, the accessibility community could strategically identify and promote technology trends that produce accessibility as a side effect. The SEO-accessibility overlap is particularly actionable — when search engines reward accessible practices like descriptive alt text, semantic headings, and meaningful link text, developers have a direct business incentive to implement them. For web developers, the paper provides concrete evidence that modern best practices (CSS layout, semantic HTML, responsive design) inherently improve accessibility, even without explicit accessibility intent. The finding that heading structure became more meaningful over time as designers used headings for visual hierarchy (which coincidentally benefits screen reader navigation) exemplifies the curb-cut effect in web development. The authors suggest that future web technologies could be intentionally designed to produce incidental accessibility benefits, and that search engines factoring accessibility into page rank could powerfully accelerate adoption.
Tags: web accessibility · WCAG · CSS · semantic markup · search engine optimization · responsive design · web standards · longitudinal study · curb cut effect · accessibility trends
Standards referenced: WCAG 1.0 · WCAG 2.0