Accessibility Fundamentals and Disability Models
This domain tests how you define disability, compare disability models, and translate those models into accessibility decisions. Expect questions that contrast the medical and social models, distinguish accessibility from usability, and ask you to classify functional needs rather than diagnose conditions.
Models in practice
- Medical model: disability is a deficiency in the person; interventions target the individual.
- Social model: disability arises from barriers in the environment, systems, and attitudes; interventions target barriers.
- Biopsychosocial / ICF: integrates body function, activity, participation, and context.
- Human rights model: access is a right, not charity; supports laws and standards.
Functional categories
Vision (blindness, low vision, color vision deficiency), hearing, motor/dexterity, speech, cognitive/learning, vestibular, seizure, and multiple disabilities. Map each to design requirements: alternatives for visuals, captions, keyboard operability, plain language, motion control, and consistent navigation.
Worked example
A stakeholder says a 3:1 text contrast failure is "the user's eyesight problem." That is medical-model framing. Under the social model, the low-contrast CSS token is the barrier; it affects low-vision users and sighted users in glare. The fix is to raise the token to at least 4.5:1 for normal text (3:1 for large text), not to ask users to adapt.
Traps
Equating WCAG conformance with complete accessibility; assuming disabilities are visible; reducing accessibility to screen readers; ignoring temporary and situational limitations; and using person-first language as a rigid rule-ask the community or follow organizational style, but do not let language debates replace barrier removal.