web-severity-scoring

name	web-severity-scoring
description	Severity scoring, scorecard computation, confidence levels, and remediation tracking for web accessibility audits. Use when computing page accessibility scores (0-100 with A-F grades), tracking remediation progress across audits, or generating cross-page comparison scorecards.

Web Severity Scoring

Severity Scoring Formula

Page Score = 100 - (sum of weighted findings)

Weights:
  Critical (high confidence, both sources):  -15 points
  Critical (high confidence, single source): -10 points
  Critical (medium confidence):               -7 points
  Critical (low confidence):                  -3 points
  Serious (high confidence):                  -7 points
  Serious (medium confidence):                -5 points
  Serious (low confidence):                   -2 points
  Moderate (high confidence):                 -3 points
  Moderate (medium confidence):               -2 points
  Moderate (low confidence):                  -1 point
  Minor:                                      -1 point

Floor: 0 (minimum score)

Score Grades

Score	Grade	Meaning
90-100	A	Excellent — minor or no issues, meets WCAG AA
75-89	B	Good — some issues, mostly meets WCAG AA
50-74	C	Needs Work — multiple issues, partial WCAG AA compliance
25-49	D	Poor — significant accessibility barriers
0-24	F	Failing — critical barriers, likely unusable with AT

Confidence Levels

Level	Weight	When to Use
High	100%	Confirmed by axe-core + agent, or definitively structural (missing alt, no labels, no lang)
Medium	70%	Found by one source, likely issue (heading edge cases, questionable ARIA, possible keyboard traps)
Low	30%	Possible issue, needs human review (alt text quality, reading order, context-dependent link text)

Source Correlation

Issues found by both axe-core AND agent review are automatically upgraded to high confidence regardless of individual confidence ratings.

Scorecard Format

Single Page

## Accessibility Score

| Metric | Value |
|--------|-------|
| Page | [URL] |
| Score | [0-100] |
| Grade | [A-F] |
| Critical | [count] |
| Serious | [count] |
| Moderate | [count] |
| Minor | [count] |

Multi-Page

## Accessibility Scorecard

| Page | Score | Grade | Critical | Serious | Moderate | Minor |
|------|-------|-------|----------|---------|----------|-------|
| / | 82 | B | 0 | 2 | 3 | 1 |
| /login | 91 | A | 0 | 0 | 2 | 1 |
| /dashboard | 45 | D | 2 | 4 | 3 | 2 |
| **Average** | **72.7** | **C** | **2** | **6** | **8** | **4** |

Cross-Page Pattern Classification

Pattern Type	Definition	Remediation ROI
Systemic	Same issue on every audited page	Highest — usually layout/nav, fix once
Template	Same issue on pages sharing a component	High — fix the shared component
Page-specific	Unique to one page	Normal — fix individually

Remediation Tracking

Change Classification

Status	Definition
Fixed	Issue was in previous report but no longer present
New	Issue not in previous report, appears now
Persistent	Issue remains from previous report
Regressed	Issue was previously fixed but has returned

Progress Metrics

• Issue reduction: (fixed / previous_total) * 100
• Score change: current_score - previous_score
• Pages improved: count of pages with higher scores than previous audit
• Trend: improving (score up 5+), stable (within 5), declining (score down 5+)

Issue Severity Categories

Critical

• No keyboard access to essential functionality
• Missing form labels on required fields
• Images conveying critical information have no alt text
• Color is the sole means of conveying information
• Keyboard traps with no escape

Serious

• Missing skip navigation
• Poor heading hierarchy (skipped levels)
• Focus not visible on interactive elements
• Form errors not programmatically associated
• Missing ARIA on custom widgets

Moderate

• Redundant ARIA on semantic elements
• Suboptimal heading structure (multiple H1s)
• Missing autocomplete on identity fields
• Links to new tabs without warning
• Missing table captions

Minor

• Redundant title attributes
• Suboptimal button text
• Missing landmark roles where semantic elements exist
• Decorative images with non-empty alt text