AARRR (Pirate Metrics)

Overview

A startup's growth is a sequential funnel — each stage gates the next. Great Acquisition is worthless if Activation is broken; great Activation is worthless if Retention is zero. Optimizing the wrong stage produces work that looks like progress while the bottleneck stays.

The AARRR framework (Dave McClure, Startup Metrics for Pirates, 2007) names five stages: Acquisition (do they show up?), Activation (good first experience?), Retention (do they come back?), Referral (do they tell others?), Revenue (do they pay?). The bottleneck stage governs total growth — improving any other stage produces no system-level gain (Goldratt, The Goal, 1984).

Compose with: first-principles to identify your specific Activation event; pmf-crossing-the-chasm to recognize when Retention will always be the bottleneck pre-PMF; probabilistic-thinking to set base rates per stage.

When to Use

• Growth is stalling and the cause is not obvious — multiple teams have plausible explanations
• Product, marketing, and sales are arguing about whose problem it is
• You need a shared instrumentation framework across teams
• Designing end-to-end metrics for a new product
• Someone says: "AARRR," "pirate metrics," "growth funnel," "where is our funnel breaking?"
• An AI-native product has strong signups but weak activation/retention — cheap AI-hype acquisition masks empty-state and post-novelty leaks; or you're facing AI-native competition on a commoditized model and need to find where your funnel actually loses users