Web Severity Scoring

web-severity-scoring Skill

Severity scoring, scorecard computation, confidence levels, and remediation tracking for web accessibility audits. Covers the page scoring formula (0-100 with A-F grades), confidence-weighted penalty calculations, source correlation rules, scorecard formats (single-page and multi-page), cross-page pattern classification, and change tracking (Fixed / New / Persistent / Regressed).

Agents That Use This Skill

Agent	Why
web-accessibility-wizard	Page scoring and audit report output
cross-page-analyzer	Cross-page scorecard and pattern scoring
accessibility-lead	Final score in orchestrated audits

Severity Scoring Formula

Page Score = 100 - (sum of weighted findings)

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

Floor: 0

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 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 review, OR definitively structural (missing alt, no labels, no lang)
Medium	70%	Found by one source - likely issue but needs judgment (heading edge cases, questionable ARIA)
Low	30%	Possible issue, needs human review (alt quality, reading order, context-dependent link text)

Source correlation rule: Issues found by both axe-core AND agent code review are automatically upgraded to high confidence, regardless of individual confidence ratings.

Scorecard Formats

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** |

Issue Severity Categories

Critical

• No keyboard access to essential functionality
• Missing form labels on required fields
• Images conveying critical information without alt text
• Color as 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
• Multiple H1s on one page
• 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

Cross-Page Pattern Classification

Pattern	Definition	Remediation ROI
Systemic	Same issue on every audited page	Highest - fix nav/layout 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

Status	Definition
Fixed	In previous report, no longer present
New	Not in previous report, appears now
Persistent	Remains from previous report
Regressed	Previously fixed, has returned

Progress Metrics

• Issue reduction: (fixed / previous_total) x 100
• Score change: current_score - previous_score
• Pages improved: count of pages with higher scores than previous audit
• Trend: Improving (+5), Stable (within 5), Declining (-5)

Skill Location

.github/skills/web-severity-scoring/SKILL.md