# Technology Evaluation Metrics

Detailed metrics and calculations used in technology stack evaluation.

---

## Table of Contents

- [Scoring and Comparison](#scoring-and-comparison)
- [Financial Calculations](#financial-calculations)
- [Ecosystem Health Metrics](#ecosystem-health-metrics)
- [Security Metrics](#security-metrics)
- [Migration Metrics](#migration-metrics)
- [Performance Benchmarks](#performance-benchmarks)

---

## Scoring and Comparison

### Technology Comparison Matrix

| Metric | Scale | Description |
|--------|-------|-------------|
| Feature Completeness | 0-100 | Coverage of required features |
| Learning Curve | Easy/Medium/Hard | Time to developer proficiency |
| Developer Experience | 0-100 | Tooling, debugging, workflow quality |
| Documentation Quality | 0-10 | Completeness, clarity, examples |

### Weighted Scoring Algorithm

The comparator uses normalized weighted scoring:

```python
# Default category weights (sum to 100%)
weights = {
    "performance": 15,
    "scalability": 15,
    "developer_experience": 20,
    "ecosystem": 15,
    "learning_curve": 10,
    "documentation": 10,
    "community_support": 10,
    "enterprise_readiness": 5
}

# Final score calculation
weighted_score = sum(category_score * weight / 100 for each category)
```

### Confidence Scoring

Confidence is calculated based on score gap between top options:

| Score Gap | Confidence Level |
|-----------|------------------|
| < 5 points | Low (40-50%) |
| 5-15 points | Medium (50-70%) |
| > 15 points | High (70-100%) |

---

## Financial Calculations

### TCO Components

**Initial Costs (One-Time)**
- Licensing fees
- Training: `team_size * hours_per_dev * hourly_rate + materials`
- Migration costs
- Setup and tooling

**Operational Costs (Annual)**
- Licensing renewals
- Hosting: `base_cost * (1 + growth_rate)^(year - 1)`
- Support contracts
- Maintenance: `team_size * hours_per_dev_monthly * hourly_rate * 12`

**Scaling Costs**
- Infrastructure: `servers * cost_per_server * 12`
- Cost per user: `total_yearly_cost / user_count`

### ROI Calculations

```
productivity_value = additional_features_per_year * avg_feature_value
net_tco = total_cost - (productivity_value * years)
roi_percentage = (benefits - costs) / costs * 100
```

### Cost Per Metric Reference

| Metric | Description |
|--------|-------------|
| Cost per user | Monthly or yearly per active user |
| Cost per API request | Average cost per 1000 requests |
| Cost per GB | Storage and transfer costs |
| Cost per compute hour | Processing time costs |

---

## Ecosystem Health Metrics

### GitHub Health Score (0-100)

| Metric | Max Points | Thresholds |
|--------|------------|------------|
| Stars | 30 | 50K+: 30, 20K+: 25, 10K+: 20, 5K+: 15, 1K+: 10 |
| Forks | 20 | 10K+: 20, 5K+: 15, 2K+: 12, 1K+: 10 |
| Contributors | 20 | 500+: 20, 200+: 15, 100+: 12, 50+: 10 |
| Commits/month | 30 | 100+: 30, 50+: 25, 25+: 20, 10+: 15 |

### npm Health Score (0-100)

| Metric | Max Points | Thresholds |
|--------|------------|------------|
| Weekly downloads | 40 | 1M+: 40, 500K+: 35, 100K+: 30, 50K+: 25, 10K+: 20 |
| Major version | 20 | v5+: 20, v3+: 15, v1+: 10 |
| Dependencies | 20 | ≤10: 20, ≤25: 15, ≤50: 10 (fewer is better) |
| Days since publish | 20 | ≤30: 20, ≤90: 15, ≤180: 10, ≤365: 5 |

### Community Health Score (0-100)

| Metric | Max Points | Thresholds |
|--------|------------|------------|
| Stack Overflow questions | 25 | 50K+: 25, 20K+: 20, 10K+: 15, 5K+: 10 |
| Job postings | 25 | 5K+: 25, 2K+: 20, 1K+: 15, 500+: 10 |
| Tutorials | 25 | 1K+: 25, 500+: 20, 200+: 15, 100+: 10 |
| Forum/Discord members | 25 | 50K+: 25, 20K+: 20, 10K+: 15, 5K+: 10 |

### Corporate Backing Score

| Backing Type | Score |
|--------------|-------|
| Major tech company (Google, Microsoft, Meta) | 100 |
| Established company (Vercel, HashiCorp) | 80 |
| Funded startup | 60 |
| Community-led (strong community) | 40 |
| Individual maintainers | 20 |

---

## Security Metrics

### Security Scoring Components

| Metric | Description |
|--------|-------------|
| CVE Count (12 months) | Known vulnerabilities in last year |
| CVE Count (3 years) | Longer-term vulnerability history |
| Severity Distribution | Critical/High/Medium/Low counts |
| Patch Frequency | Average days to patch vulnerabilities |

### Compliance Readiness Levels

| Level | Score Range | Description |
|-------|-------------|-------------|
| Ready | 90-100% | Meets compliance requirements |
| Mostly Ready | 70-89% | Minor gaps to address |
| Partial | 50-69% | Significant work needed |
| Not Ready | < 50% | Major gaps exist |

### Compliance Framework Coverage

**GDPR**
- Data privacy features
- Consent management
- Data portability
- Right to deletion

**SOC2**
- Access controls
- Encryption at rest/transit
- Audit logging
- Change management

**HIPAA**
- PHI handling
- Encryption standards
- Access controls
- Audit trails

---

## Migration Metrics

### Complexity Scoring (1-10 Scale)

| Factor | Weight | Description |
|--------|--------|-------------|
| Code Changes | 30% | Lines of code affected |
| Architecture Impact | 25% | Breaking changes, API compatibility |
| Data Migration | 25% | Schema changes, data transformation |
| Downtime Requirements | 20% | Zero-downtime possible vs planned outage |

### Effort Estimation

| Phase | Components |
|-------|------------|
| Development | Hours per component * complexity factor |
| Testing | Unit + integration + E2E hours |
| Training | Team size * learning curve hours |
| Buffer | 20-30% for unknowns |

### Risk Assessment Matrix

| Risk Category | Factors Evaluated |
|---------------|-------------------|
| Technical | API incompatibilities, performance regressions |
| Business | Downtime impact, feature parity gaps |
| Team | Learning curve, skill gaps |

---

## Performance Benchmarks

### Throughput/Latency Metrics

| Metric | Description |
|--------|-------------|
| RPS | Requests per second |
| Avg Response Time | Mean response latency (ms) |
| P95 Latency | 95th percentile response time |
| P99 Latency | 99th percentile response time |
| Concurrent Users | Maximum simultaneous connections |

### Resource Usage Metrics

| Metric | Unit |
|--------|------|
| Memory | MB/GB per instance |
| CPU | Utilization percentage |
| Storage | GB required |
| Network | Bandwidth MB/s |

### Scalability Characteristics

| Type | Description |
|------|-------------|
| Horizontal | Add more instances, efficiency factor |
| Vertical | CPU/memory limits per instance |
| Cost per Performance | Dollar per 1000 RPS |
| Scaling Inflection | Point where cost efficiency changes |
