WaaT: Personalised Web Accessibility Evaluation Tool
Theofanis Oikonomou, Nikolaos Kaklanis, Konstantinos Votis, Grammati-Eirini Kastori, Nikolaos Partarakis, Dimitrios Tzovaras · 2011 · Proceedings of the International Cross-Disciplinary Conference on Web Accessibility (W4A) · doi:10.1145/1969289.1969315
Summary
This paper presents WaaT (Web Accessibility Assessment Tool), a personalized accessibility evaluation tool that allows developers to assess web content against specific disability profiles, assistive technologies, and personas rather than running a generic WCAG 2.0 audit. Developed at the Centre for Research and Technology-Hellas (CERTH) in Greece as part of the EU FP7 ACCESSIBLE project, WaaT combines WCAG 2.0 with the Barrier Walkthrough methodology through an ontology-based framework called HAM (Harmonized Assessment Methodology). The key innovation is personalization: instead of checking all WCAG success criteria uniformly, the tool selects only the relevant subset of tests based on the evaluator's chosen disability profile, impairment combination, or persona. For example, selecting the persona "Emma Karlsson" (who has Dysarthria, Expressive language disorder, Conductive hearing loss, and Communication disability) returns only the WCAG approaches and checks relevant to those specific impairments. The tool uses WHO's International Classification of Functioning, Disability and Health (ICF) as the core vocabulary for describing disability profiles, giving it a standardized clinical foundation. The system integrates the CyberNeko HTML Parser with Groovy scripts for HTML/XHTML analysis, the W3C Markup Validator, the W3C CSS Validator, and an EARL Report Generator for machine-readable (RDF) and human-readable (PDF) output.
Key findings
WaaT supports multiple personalization dimensions: disability categories (upper limb impairment, cognitive, vision, communication), specific impairments within categories, functional limitations, assistive technologies, software platforms, and pre-defined personas representing combinations of impairments. The evaluation output groups errors and warnings by WCAG 2.0 Success Criterion priority level, with assistive tips for remediation and source code highlighting showing exactly where problems occur. A manual verification feature allows evaluators to review warnings and decide whether each is a genuine error or should be ignored. An initial evaluation with 122 participants (accessibility experts, developers, designers) who evaluated their favorite websites informed UI improvements and test coverage. Future evaluation with disabled users was planned. The ontology-based approach allows richer semantic querying of accessibility knowledge than simpler guideline selection frameworks, enabling the system to reason about relationships between impairments, barriers, and applicable guidelines.
Relevance
WaaT addresses a genuine limitation of most accessibility evaluation tools: they treat WCAG as a monolithic checklist, producing overwhelming results that don't help developers understand which issues affect which users. By connecting specific impairments to relevant WCAG criteria through the ICF ontology and Barrier Walkthrough methodology, the tool helps prioritize remediation based on actual user impact. The persona-based approach makes accessibility evaluation more concrete and empathetic — fixing issues for "Emma Karlsson" is more motivating than fixing abstract WCAG violations. The use of ICF as a standardized disability vocabulary is a strength that connects web accessibility to the broader health and rehabilitation classification system. However, the paper presents the tool without comparative evaluation against existing tools, and the initial 122-participant study did not include people with disabilities. The concept of disability-profile-filtered evaluation has since been partially adopted in some modern tools that allow filtering by disability category, though few match WaaT's ontological sophistication.
Tags: accessibility evaluation · automated testing · WCAG compliance · accessibility tools · personas · barrier walkthrough · ontology
Standards referenced: WCAG 2.0 · EARL · ICF