WCAG (Web Content Accessibility Guidelines)
This post is a glossary entry for WCAG, including exam questions, core components, and key terms.
In a Nutshell
WCAG defines testable success criteria for accessibility across four principles:
- perceivable
- operable
- understandable
- robust
The typical target standard in projects is WCAG AA.
Concise Technical Overview
WCAG (from the W3C) has three conformance levels:
- A (minimum)
- AA (practical standard)
- AAA (enhanced, not always realistic)
The four principles together form the acronym POUR.
Common success criteria include:
- contrast (AA typically requires 4.5:1 for body text)
- keyboard operability
- visible focus indicators
- clear labels and error messages
Implementation approach:
- semantic HTML before ARIA
- logical tab order
- focus management
- understandable error handling
Verification: automated scanning plus manual review plus keyboard and screen reader testing.
Exam-Relevant Checklist
- Explain POUR
- Distinguish between levels A/AA/AAA
- State contrast ratios
- Keyboard navigation and visible focus
- Testing methods: scanners, manual testing, assistive technology
- Documentation: checklists, test reports, style guides
- Connection to EN 301 549 (EU standard)
Core Components
- Principles and success criteria
- Target level (AA) and scope
- Semantic markup and structure
- Keyboard operability
- Contrast and perceivability
- Labels, names, and roles
- Error prevention and messaging
- Media alternatives
- Robust code and correct ARIA usage
- QA process and test documentation
Practical Example (Form)
- visible labels with programmatic association
- tab order is linear; focus indicators are visible
- error list links to fields; messages appear near fields
- contrast at least 4.5:1 for text
- accessibility checklist and test report in repository
Typical Exam Questions (with Brief Answers)
- What does POUR stand for? Perceivable, Operable, Understandable, Robust.
- What is the AA contrast ratio for body text? At least 4.5:1.
- How do you test efficiently? Automated scanning plus manual review plus keyboard and screen reader testing.