# 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

---

## 1. Success Criteria Framework

### SMART Metrics Definition:
- **S**pecific: Clear, unambiguous measure
- **M**easurable: Quantifiable data
- **A**chievable: Realistic given constraints
- **R**elevant: Aligned with project goals
- **T**ime-bound: Deadline for achievement

---

## 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**:
```bash
npm test -- --coverage
# Output: Coverage summary
```

**Success Thresholds**:
- ✅ Excellent: ≥ 90%
- ⚠️ Acceptable: 80-89%
- ❌ Needs Improvement: < 80%

**Current Baseline**: TBD (measure after Phase 1)

---

#### 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

---

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

---

### 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**:
```bash
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)

---

#### 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**:
```javascript
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

---

#### 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**:
```javascript
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

---

#### 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**:
```bash
du -h dist/*
gzip -c dist/main.js | wc -c
```

**Success Thresholds**:
- ✅ Excellent: < 100KB uncompressed
- ⚠️ Acceptable: 100-200KB
- ❌ Needs Optimization: > 200KB

---

### 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

---

#### 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

---

#### 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**:
```javascript
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**:
```javascript
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)

---

#### 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)

---

#### 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)

---

#### 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

---

### 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)

---

#### 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)

---

#### 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)

---

## 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)

---

#### 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%

---

#### 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%

---

## 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

---

#### 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

---

#### 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)

---

#### 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

---

### 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

---

#### 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

---

#### 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)

---

## 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

---

#### 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

---

## 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)

---

## 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

---

## 9. Data Collection Methods

### Automated Metrics:
```javascript
// 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)

---

## 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.