# Success Metrics Framework

## North Star Metric

### Definition
The single metric that best represents the core value delivered by the product.

### Selection Principles
1. Reflects user value
2. Aligns with business objectives
3. Measurable and trackable
4. Understandable and influenceable by the team

### Examples
| Product Type | North Star Metric |
|--------------|-------------------|
| E-commerce | Monthly Active Purchasing Users |
| Content Platform | Average Monthly Usage Time per User |
| SaaS | Monthly Active Subscribers |
| Social | Daily Active Users (DAU) |
| Utility/Tool | Weekly Completed Tasks |

## Key Results (KRs)

### OKR Framework
```
Objective: Improve user retention
KR1: Increase 30-day retention rate from 20% to 30%
KR2: Grow Monthly Active Users (MAU) by 50%
KR3: Increase average user frequency from 2 times per week to 4 times per week
```

### SMART Principles
- Specific
- Measurable
- Achievable
- Relevant
- Time-bound

## Monitoring Metric Hierarchy

### 1. Business Metrics
- Revenue, Profit
- User Growth
- Market Share

### 2. Product Metrics
- Active Users (DAU/MAU)
- Retention Rate
- Conversion Rate
- Time Spent

### 3. Feature Metrics
- Feature Adoption Rate
- Feature Satisfaction
- Feature Conversion Funnel

### 4. Technical Metrics
- Performance Metrics (Response time, Load speed)
- Stability (Crash rate, Error rate)
- Availability (SLA)

## Common Metric Formulas

### User Growth
```
Customer Acquisition Cost (CAC) = Marketing Expenses / New Users Acquired
Customer Lifetime Value (LTV) = ARPU × Customer Lifetime
LTV/CAC > 3 indicates healthy growth
```

### Retention Analysis
```
Day 1 Retention Rate = Returning Users on Day 2 / New Users on Day 1
Day 7 Retention Rate = Returning Users on Day 7 / New Users on Day 1
Day 30 Retention Rate = Returning Users on Day 30 / New Users on Day 1
```

### Engagement
```
DAU/MAU Ratio = Daily Active Users / Monthly Active Users
> 20% indicates strong product stickiness
```

### Conversion Rate
```
Conversion Rate = Number of Users Completing Goal / Number of Visitors
```

## Data Tracking Plan

### Event Tracking Design
1. Define key events
2. Design event properties
3. Plan user properties
4. Establish a data dictionary

### Analytics Tools
- Google Analytics
- Mixpanel
- Amplitude
- Custom-built data platform

## Metrics Dashboard

### Real-time Monitoring
- DAU/MAU
- Key conversion rates
- Error rate

### Periodic Reviews
- Weekly Report: Growth trends, anomaly fluctuations
- Monthly Report: Metric changes, attribution analysis
- Quarterly Report: Goal achievement, strategy adjustments