chess/docs/analysis/success-metrics.md

Success Metrics: HTML Chess Game

Executive Summary

Measurement Framework: SMART metrics across 6 categories KPIs: 32 key performance indicators Success Threshold: 70% of critical metrics met Review Frequency: Weekly sprints, monthly milestones

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1. Success Criteria Framework

SMART Metrics Definition:

• Specific: Clear, unambiguous measure
• Measurable: Quantifiable data
• Achievable: Realistic given constraints
• Relevant: Aligned with project goals
• Time-bound: Deadline for achievement

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2. Technical Success Metrics

2.1 Code Quality (Weight: 25%)

M1: Test Coverage

Target: ≥ 90% | Measurement: Jest coverage report | Priority: CRITICAL

Acceptance Criteria:

• Chess engine (move validation): ≥ 95%
• AI engine (minimax): ≥ 85%
• UI components: ≥ 80%
• Utility functions: ≥ 95%

Measurement Method:

npm test -- --coverage
# Output: Coverage summary

Success Thresholds:

• ✅ Excellent: ≥ 90%
• ⚠️ Acceptable: 80-89%
• ❌ Needs Improvement: < 80%

Current Baseline: TBD (measure after Phase 1)

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M2: Zero Critical Bugs

Target: 0 bugs | Measurement: Bug tracker | Priority: CRITICAL

Bug Severity Definitions:

• Critical: Game unplayable, data loss, crashes
• High: Major feature broken, incorrect rules
• Medium: UI issues, minor rule violations
• Low: Cosmetic issues, typos

Success Criteria:

• ✅ 0 critical bugs in production
• ✅ < 3 high-severity bugs
• ⚠️ < 10 medium-severity bugs
• ℹ️ Low bugs acceptable

Measurement Method: GitHub Issues with severity labels

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M3: Code Maintainability

Target: A grade | Measurement: Static analysis | Priority: HIGH

Metrics:

• Cyclomatic complexity: < 15 per function
• Lines per file: < 500
• Function length: < 50 lines
• Comment density: 10-20%

Tools:

• ESLint (linting)
• SonarQube or CodeClimate (complexity)
• Manual code review

Success Thresholds:

• ✅ A Grade: All metrics within targets
• ⚠️ B Grade: 1-2 metrics slightly over
• ❌ C Grade: Multiple violations

---

M4: Chess Rules Compliance

Target: 100% | Measurement: Test suite | Priority: CRITICAL

Test Cases:

• All piece movements (100+ test cases)
• Special moves (castling, en passant, promotion)
• Check/checkmate/stalemate detection
• Draw conditions (50-move, repetition, insufficient material)

Success Criteria:

• ✅ Pass all FIDE rule tests
• ✅ Validate against known positions (Lichess puzzle database)
• ✅ No illegal moves possible

Measurement Method:

describe('FIDE Rules Compliance', () => {
  test('All legal moves are allowed', () => {...});
  test('All illegal moves are blocked', () => {...});
  test('Edge cases handled correctly', () => {...});
});

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2.2 Performance Metrics (Weight: 20%)

M5: Page Load Time

Target: < 1s | Measurement: Lighthouse | Priority: HIGH

Metrics:

• First Contentful Paint (FCP): < 500ms
• Largest Contentful Paint (LCP): < 1s
• Time to Interactive (TTI): < 2s
• Cumulative Layout Shift (CLS): < 0.1

Measurement Method:

lighthouse https://your-chess-app.com --view

Success Thresholds:

• ✅ Excellent: All metrics green (Lighthouse 90+)
• ⚠️ Acceptable: 1-2 yellow metrics (Lighthouse 70-89)
• ❌ Needs Work: Red metrics (Lighthouse < 70)

Current Baseline: TBD (measure after deployment)

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M6: AI Response Time

Target: < 1s (beginner), < 2s (intermediate) | Measurement: Performance API | Priority: CRITICAL

Targets by Difficulty:

• Beginner AI (depth 3-4): < 500ms
• Intermediate AI (depth 5-6): < 1.5s
• Advanced AI (depth 7+): < 5s

Measurement Method:

const start = performance.now();
const move = calculateBestMove(position, depth);
const duration = performance.now() - start;
console.log(`AI calculated in ${duration}ms`);

Success Criteria:

• ✅ 95th percentile under target
• ⚠️ Median under target, p95 over
• ❌ Median over target

Device Targets:

• Desktop: Full performance
• Mobile (high-end): 1.5x slower acceptable
• Mobile (low-end): 2.5x slower acceptable

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M7: Frame Rate (Animations)

Target: 60fps | Measurement: Chrome DevTools | Priority: MEDIUM

Acceptance Criteria:

• ✅ Piece movement: 60fps (16ms/frame)
• ✅ Highlights: 60fps
• ⚠️ Occasional dips to 50fps acceptable
• ❌ Consistent < 30fps unacceptable

Measurement Method:

let frameCount = 0;
let lastTime = performance.now();

function measureFPS() {
  frameCount++;
  const now = performance.now();
  if (now - lastTime >= 1000) {
    console.log(`FPS: ${frameCount}`);
    frameCount = 0;
    lastTime = now;
  }
  requestAnimationFrame(measureFPS);
}

Success Threshold:

• ✅ Average FPS ≥ 58
• ⚠️ Average FPS 45-57
• ❌ Average FPS < 45

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M8: Memory Usage

Target: < 50MB | Measurement: Chrome DevTools | Priority: MEDIUM

Acceptance Criteria:

• Initial load: < 20MB
• After 50 moves: < 40MB
• After 100 moves: < 60MB
• No memory leaks (stable over time)

Measurement Method: Chrome DevTools → Memory → Take heap snapshot

Success Criteria:

• ✅ Memory stable after 10 minutes
• ⚠️ Slow growth (< 1MB/min)
• ❌ Memory leak (> 5MB/min)

---

M9: Bundle Size

Target: < 100KB | Measurement: Build output | Priority: MEDIUM

Component Breakdown:

• HTML: < 5KB
• CSS: < 10KB
• JavaScript: < 60KB
• Assets (SVG pieces): < 25KB
• Total (gzipped): < 40KB

Measurement Method:

du -h dist/*
gzip -c dist/main.js | wc -c

Success Thresholds:

• ✅ Excellent: < 100KB uncompressed
• ⚠️ Acceptable: 100-200KB
• ❌ Needs Optimization: > 200KB

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2.3 Reliability Metrics (Weight: 15%)

M10: Uptime (if hosted)

Target: 99.9% | Measurement: UptimeRobot | Priority: MEDIUM

Acceptable Downtime:

• Per month: < 43 minutes
• Per week: < 10 minutes
• Per day: < 1.5 minutes

Measurement Method: Automated monitoring service

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M11: Browser Compatibility

Target: 95% support | Measurement: Manual testing | Priority: HIGH

Supported Browsers:

• Chrome/Edge (last 2 versions): ✅ Full support
• Firefox (last 2 versions): ✅ Full support
• Safari (last 2 versions): ✅ Full support
• Mobile Safari iOS 14+: ✅ Full support
• Chrome Android: ✅ Full support

Success Criteria:

• ✅ No game-breaking bugs in supported browsers
• ⚠️ Minor visual differences acceptable
• ❌ Core features broken

Measurement Method: BrowserStack testing matrix

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M12: Error Rate

Target: < 0.1% | Measurement: Error tracking (Sentry) | Priority: MEDIUM

Metrics:

• JavaScript errors per 1000 sessions: < 1
• Failed moves: 0 (should be validated)
• UI crashes: 0

Measurement Method:

window.addEventListener('error', (event) => {
  // Log to error tracking service
  console.error('Error:', event.error);
});

Success Threshold:

• ✅ < 0.1% error rate
• ⚠️ 0.1-0.5% error rate
• ❌ > 0.5% error rate

---

3. User Experience Metrics (Weight: 20%)

3.1 Usability Metrics

M13: Time to First Move

Target: < 30s | Measurement: Analytics | Priority: HIGH

User Journey:

1. Land on page (0s)
2. Understand it's a chess game (2-5s)
3. Click first piece (10-20s)
4. Make first move (20-30s)

Success Criteria:

• ✅ Median time < 30s
• ⚠️ Median time 30-60s
• ❌ Median time > 60s

Measurement Method:

const pageLoadTime = performance.timing.navigationStart;
const firstMoveTime = Date.now();
const timeToFirstMove = firstMoveTime - pageLoadTime;

---

M14: Completion Rate

Target: > 60% | Measurement: Analytics | Priority: MEDIUM

Definition: % of started games that reach checkmate/stalemate/resignation

Success Criteria:

• ✅ > 70% completion rate
• ⚠️ 50-70% completion rate
• ❌ < 50% completion rate

Baseline Expectation:

• Beginner AI: 80% (users play to conclusion)
• Intermediate AI: 60% (some abandon if losing)
• Advanced AI: 40% (frustration leads to abandonment)

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M15: User Satisfaction Score (SUS)

Target: > 70 | Measurement: User survey | Priority: HIGH

System Usability Scale (SUS) Survey: 10 questions, 1-5 scale, industry-standard

Questions:

1. I think I would like to use this system frequently
2. I found the system unnecessarily complex (reverse)
3. I thought the system was easy to use
4. I think I would need support to use this system (reverse)
5. I found the various functions well integrated ... (standard SUS questions)

Success Thresholds:

• ✅ SUS > 80 (Excellent)
• ⚠️ SUS 68-80 (Good)
• ✅ SUS > 70 (Acceptable - our target)
• ❌ SUS < 68 (Below average)

Measurement Method: Post-game survey (optional popup)

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M16: Net Promoter Score (NPS)

Target: > 50 | Measurement: Survey | Priority: MEDIUM

Question: "How likely are you to recommend this chess game to a friend?" (0-10)

Calculation:

• Promoters (9-10): % of respondents
• Detractors (0-6): % of respondents
• NPS = % Promoters - % Detractors

Success Thresholds:

• ✅ NPS > 50 (Excellent)
• ⚠️ NPS 20-50 (Good)
• ✅ NPS > 0 (Acceptable - our target)
• ❌ NPS < 0 (Needs improvement)

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M17: Task Success Rate

Target: > 95% | Measurement: User testing | Priority: HIGH

Tasks:

1. Start a new game (100% should succeed)
2. Make a legal move (100%)
3. Undo a move (98%)
4. Change difficulty (95%)
5. Understand when in check (90%)
6. Recognize checkmate (90%)

Success Criteria:

• ✅ All tasks > 90% success rate
• ⚠️ 1-2 tasks 80-90%
• ❌ Any task < 80%

Measurement Method: 5-10 user testing sessions, record successes

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3.2 Engagement Metrics

M18: Average Session Duration

Target: > 5 minutes | Measurement: Analytics | Priority: MEDIUM

Expectations:

• Quick game: 3-5 minutes
• Normal game: 10-15 minutes
• Long game: 20+ minutes

Success Criteria:

• ✅ Median session > 8 minutes
• ⚠️ Median session 5-8 minutes
• ❌ Median session < 5 minutes (users leaving quickly)

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M19: Games per Session

Target: > 2 | Measurement: Analytics | Priority: MEDIUM

Success Criteria:

• ✅ Average > 2.5 games/session (high engagement)
• ⚠️ Average 1.5-2.5 games
• ❌ Average < 1.5 games (play once and leave)

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M20: Return Rate (7-day)

Target: > 30% | Measurement: Analytics | Priority: MEDIUM

Definition: % of users who return within 7 days

Success Criteria:

• ✅ > 40% return rate
• ⚠️ 30-40% return rate
• ❌ < 30% return rate

Measurement Method: Cookie/localStorage tracking (privacy-respecting)

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4. Feature Adoption Metrics (Weight: 10%)

M21: AI Mode Usage

Target: > 60% | Measurement: Analytics | Priority: MEDIUM

Definition: % of users who play at least one game vs AI

Success Criteria:

• ✅ > 70% try AI mode
• ⚠️ 50-70% try AI mode
• ❌ < 50% (AI feature underutilized)

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M22: Undo Usage Rate

Target: 20-40% | Measurement: Analytics | Priority: LOW

Definition: % of moves that are undone

Interpretation:

• < 10%: Users afraid to use (bad UX)
• 20-40%: Healthy usage (learning, correcting)

• 60%: Overused (too easy? unclear rules?)

Success Criteria:

• ✅ 20-40% undo rate
• ⚠️ 10-20% or 40-60%
• ❌ < 10% or > 60%

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M23: Feature Discovery Rate

Target: > 80% | Measurement: Analytics | Priority: MEDIUM

Features to Track:

• New game button: 100%
• Undo button: 80%+
• Difficulty selector: 70%+
• Flip board: 30%+
• Settings: 50%+

Success Criteria:

• ✅ All core features > 80% discovery
• ⚠️ 1-2 features 60-80%
• ❌ Core features < 60%

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5. Business/Project Metrics (Weight: 10%)

5.1 Development Metrics

M24: Velocity (Story Points/Sprint)

Target: Consistent | Measurement: Sprint tracking | Priority: HIGH

Measurement:

• Track story points completed per sprint
• Calculate average velocity
• Monitor variance

Success Criteria:

• ✅ Velocity stable (±20%)
• ⚠️ Velocity fluctuates (±40%)
• ❌ Velocity highly unpredictable (> 50% variance)

Baseline: Establish in first 2 sprints

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M25: Sprint Goal Achievement

Target: > 80% | Measurement: Sprint retrospective | Priority: HIGH

Definition: % of sprint goals fully completed

Success Criteria:

• ✅ > 90% of sprints hit goals
• ⚠️ 70-90% of sprints
• ❌ < 70% of sprints

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M26: Technical Debt Ratio

Target: < 5% | Measurement: Time tracking | Priority: MEDIUM

Definition: Time spent fixing bugs/refactoring vs building features

Success Criteria:

• ✅ < 5% time on debt
• ⚠️ 5-15% time on debt
• ❌ > 15% time on debt (too much debt)

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M27: Deadline Adherence

Target: 100% | Measurement: Project milestones | Priority: CRITICAL

Milestones:

• MVP (Week 6): ±1 week acceptable
• Phase 2 (Week 10): ±1 week acceptable
• Phase 3 (Week 14): ±2 weeks acceptable

Success Criteria:

• ✅ All milestones within buffer
• ⚠️ 1 milestone delayed > buffer
• ❌ Multiple delayed or major delay

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5.2 Adoption Metrics

M28: Total Users (if public)

Target: 1000 in first month | Measurement: Analytics | Priority: MEDIUM

Growth Targets:

• Week 1: 100 users
• Week 2: 300 users
• Week 4: 1000 users
• Month 3: 5000 users

Success Criteria:

• ✅ Hit growth targets
• ⚠️ 50-80% of targets
• ❌ < 50% of targets

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M29: Bounce Rate

Target: < 40% | Measurement: Analytics | Priority: MEDIUM

Definition: % of users who leave without interacting

Success Criteria:

• ✅ < 30% bounce rate
• ⚠️ 30-50% bounce rate
• ❌ > 50% bounce rate

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M30: Referral Traffic

Target: > 20% | Measurement: Analytics | Priority: LOW

Definition: % of traffic from referrals (not direct/search)

Success Criteria:

• ✅ > 30% referral traffic (good word-of-mouth)
• ⚠️ 15-30% referral traffic
• ❌ < 15% (not being shared)

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6. Accessibility Metrics (Weight: 5%)

M31: WCAG 2.1 Compliance

Target: AA level | Measurement: Automated + manual testing | Priority: HIGH

Requirements:

• Color contrast ratio: ≥ 4.5:1
• Keyboard navigation: Full support
• Screen reader compatibility: ARIA labels
• Alt text on images: 100%
• Focus indicators: Visible

Success Criteria:

• ✅ WCAG AA compliant (0-3 violations)
• ⚠️ Minor violations (4-10)
• ❌ Major violations (> 10)

Tools:

• axe DevTools
• Lighthouse accessibility audit
• Manual screen reader testing

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M32: Keyboard Navigation Success

Target: 100% | Measurement: Manual testing | Priority: HIGH

Tasks:

• Tab through all interactive elements
• Select piece with keyboard
• Move piece with keyboard
• Access all menus/buttons
• No keyboard traps

Success Criteria:

• ✅ All tasks possible without mouse
• ⚠️ 1-2 minor issues
• ❌ Critical features inaccessible

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7. Measurement Dashboard

Weekly Metrics Review:

• Test coverage (M1)
• Critical bugs (M2)
• AI response time (M6)
• Sprint velocity (M24)
• Sprint goal achievement (M25)

Monthly Metrics Review:

• All technical metrics (M1-M12)
• User satisfaction (M15)
• Engagement metrics (M18-M20)
• Milestone adherence (M27)
• Accessibility compliance (M31-M32)

Release Metrics (Before Deployment):

• 100% chess rules compliance (M4)
• Lighthouse score > 90 (M5)
• Zero critical bugs (M2)
• Cross-browser testing (M11)
• WCAG AA compliance (M31)

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8. Success Scorecard

Critical Metrics (Must Pass All):

1. ✅ Test coverage ≥ 90% (M1)
2. ✅ Zero critical bugs (M2)
3. ✅ 100% chess rules compliance (M4)
4. ✅ AI response time < targets (M6)
5. ✅ Lighthouse > 90 (M5)
6. ✅ Deadline adherence (M27)

Result: PASS/FAIL (all must pass for successful release)

High Priority Metrics (≥ 80% Must Pass):

• Code maintainability (M3)
• Frame rate 60fps (M7)
• Browser compatibility (M11)
• Time to first move < 30s (M13)
• Task success rate > 95% (M17)
• Keyboard navigation (M32)

Result: 6/8 must pass (75%)

Medium Priority Metrics (≥ 60% Should Pass):

• Bundle size (M9)
• Memory usage (M8)
• Completion rate (M14)
• Session duration (M18)
• Feature adoption (M21-M23)

Result: Nice-to-have, doesn't block release

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9. Data Collection Methods

Automated Metrics:

// Performance monitoring
window.addEventListener('load', () => {
  const perfData = performance.timing;
  const loadTime = perfData.loadEventEnd - perfData.navigationStart;
  logMetric('page_load_time', loadTime);
});

// User actions
function trackMove(from, to) {
  logEvent('move_made', { from, to, timestamp: Date.now() });
}

// Session tracking
const sessionStart = Date.now();
window.addEventListener('beforeunload', () => {
  const sessionDuration = Date.now() - sessionStart;
  logMetric('session_duration', sessionDuration);
});

Manual Metrics:

• Weekly code reviews (M3)
• Monthly user testing (M17)
• Sprint retrospectives (M25)
• Quarterly accessibility audits (M31)

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10. Reporting Format

Weekly Progress Report:

# Week N Progress Report

## Development Metrics:
- Velocity: 23 points (target: 20-25) ✅
- Sprint goal: 85% complete ⚠️
- Bugs: 2 high, 5 medium ✅
- Test coverage: 88% ⚠️ (target: 90%)

## Performance:
- AI response time: 450ms ✅
- Page load: 800ms ✅
- Bundle size: 95KB ✅

## Blockers:
- Castling edge case failing tests (in progress)

## Next Week Focus:
- Reach 90% test coverage
- Complete Phase 1 features
- Fix high-severity bugs

---

Conclusion

32 Success Metrics Defined across 6 categories:

1. Technical Quality (25%)
2. Performance (20%)
3. User Experience (20%)
4. Feature Adoption (10%)
5. Business/Project (10%)
6. Accessibility (5%)

Critical Success Factors:

• 100% chess rules compliance
• Zero critical bugs
• ≥ 90% test coverage
• AI response times < 1s
• Lighthouse score > 90
• On-time delivery

Review Cadence:

• Daily: Bug counts, build status
• Weekly: Development velocity, technical metrics
• Monthly: User metrics, milestone progress
• Release: Full scorecard review

Success Threshold:

• Pass ALL 6 critical metrics
• Pass ≥ 80% of high-priority metrics
• Pass ≥ 60% of medium-priority metrics

Measurement Tools:

• Jest (test coverage)
• Lighthouse (performance)
• Chrome DevTools (profiling)
• Analytics (user behavior)
• Manual testing (usability)

With this measurement framework, success is objectively defined and trackable throughout the project lifecycle.