Accessibility Testing Strategy
Plan a testing approach that catches real accessibility barriers — because automated tools find roughly 30% of issues. The other 70% require human judgment.
The Testing Pyramid
Layer 1: Automated Testing (Catches ~30%)
What it finds:
- Missing alt text
- Colour contrast failures
- Missing form labels
- Missing language attribute
- Empty headings and buttons
- Duplicate IDs
What it misses:
- Whether alt text is meaningful
- Whether focus order is logical
- Whether content makes sense
- Whether interactions work with keyboard
- Whether the experience is usable
Tools: axe, Lighthouse, WAVE, Pa11y, jest-axe When: on every build, in CI/CD pipeline Who: automated — no human needed
Layer 2: Manual Expert Testing (Catches ~50%)
What it finds:
- Keyboard navigation issues
- Focus management problems
- Logical reading order failures
- Meaningful alt text assessment
- Cognitive accessibility barriers
- Interaction pattern issues
Method:
- Tab through every interactive element
- Test with screen reader (VoiceOver or NVDA)
- Test at 200% zoom
- Test with system preferences enabled
- Review content for plain language
When: before each release, on major feature changes Who: someone trained in accessibility testing
Layer 3: User Testing With Disabled People (Catches remaining ~20%)
What it finds:
- Real-world usability barriers that experts miss
- Assistive technology compatibility issues
- Unexpected workflows and workarounds
- Cognitive and emotional barriers
- Issues that only appear with actual AT proficiency
Method:
- Recruit participants with diverse disabilities
- Test core tasks with their own devices and AT
- Observe — don't guide or explain
- Record what works, what fails, and what frustrates
When: quarterly, or before major launches Who: users with disabilities using their own setup
What to Test First
Priority 1: Core Tasks
- Can users complete the primary tasks the product exists for?
- Test the critical path end to end
- Any failure here is a launch blocker
Priority 2: Input and Navigation
- Keyboard-only navigation through the core flow
- Screen reader navigation through the core flow
- Touch interaction on mobile for the core flow
Priority 3: Content and Comprehension
- Is content understandable at the target reading level?
- Are error messages helpful?
- Is help available and findable?
Priority 4: Edge Cases and Preferences
- Zoom to 200%
- System preferences (reduced motion, high contrast, dark mode)
- Long content, empty states, error states
Screen Reader Testing Basics
For teams new to screen reader testing:
Start With VoiceOver (Mac)
- Turn on: Cmd + F5
- Navigate: VO + arrow keys (VO = Ctrl + Option)
- Headings: VO + Cmd + H
- Links: VO + Cmd + L
- Forms: VO + Cmd + J
- Turn off: Cmd + F5
Start With NVDA (Windows)
- Download free from nvaccess.org
- Navigate: Tab, arrow keys
- Headings: H
- Links: K
- Forms: F
- Stop speech: Ctrl
What to Listen For
- Does every interactive element have a name?
- Are state changes announced (expanded, selected, checked)?
- Does focus move to the right place after actions?
- Can you understand the page reading only the headings?
Assessment Questions
- Is automated testing running on every build?
- Is manual expert testing happening before each release?
- Has the product been tested by people with disabilities?
- Are core tasks tested with keyboard and screen reader?
- Is there a clear priority for what to test first?
