metrics-tree

# Metrics Tree

## Table of Contents
- [Purpose](#purpose)
- [When to Use](#when-to-use)
- [What Is It](#what-is-it)
- [Workflow](#workflow)
- [Common Patterns](#common-patterns)
- [Guardrails](#guardrails)
- [Quick Reference](#quick-reference)

## Purpose

Decompose high-level "North Star" metrics into actionable sub-metrics, identify leading indicators, understand causal relationships, and select high-impact experiments to move metrics.

## When to Use

Use metrics-tree when you need to:

**Define Strategy:**
- Setting a North Star metric for product/business
- Aligning teams around single most important metric
- Clarifying what success looks like quantitatively
- Connecting strategic goals to measurable outcomes

**Understand Metrics:**
- Decomposing complex metrics into component drivers
- Identifying what actually moves a high-level metric
- Understanding causal relationships between metrics
- Distinguishing leading vs lagging indicators
- Mapping metric interdependencies

**Prioritize Actions:**
- Deciding which sub-metrics to focus on
- Identifying highest-leverage improvement opportunities
- Selecting experiments that will move North Star
- Allocating resources across metric improvement efforts
- Understanding tradeoffs between metric drivers

**Diagnose Issues:**
- Investigating why a metric is declining
- Finding root causes of metric changes
- Identifying bottlenecks in metric funnels
- Troubleshooting unexpected metric behavior

## What Is It

A metrics tree decomposes a North Star metric (the single most important product/business metric) into its component drivers, creating a hierarchy of related metrics with clear causal relationships.

**Key Concepts:**

**North Star Metric:** Single metric that best captures core value delivered to customers and predicts long-term business success. Examples:
- Airbnb: Nights booked
- Netflix: Hours watched
- Slack: Messages sent by teams
- Uber: Rides completed
- Stripe: Payment volume

**Metric Levels:**
1. **North