The Four Severity Levels
Critical — Fix Immediately
Blocks access to core functionality. A screen reader user cannot access the content, or a keyboard-only user is locked out. Examples: images with no alt text conveying essential info, form inputs without labels, non-keyboard-accessible interactive elements.
Serious — Fix Promptly
Significantly impairs experience. Users can access content but with considerable difficulty. Examples: low contrast text, skipped heading levels, ambiguous link text like “click here.”
Moderate — Plan to Fix
Creates barriers but workarounds exist. Examples: missing language attributes on content blocks, suspicious alt text (filenames as descriptions), tables without proper headers.
Minor — Address When Possible
Best-practice violations with minimal access impact. Examples: redundant ARIA attributes, minor tab order inconsistencies, deprecated markup patterns.
Prioritization Strategy
Address issues in severity order: Critical first, then Serious, Moderate, Minor. Within each level, prioritize your most visited pages and issues affecting the most users.