“Pirate Metrics” refers to a framework for measuring and tracking the growth of a business or product, developed by Dave McClure of 500 Startups. The pirate metrics framework includes the following five stages: Acquisition (A), Activation (A), Retention (R), Revenue (R), and Referral (R). In product management, understanding and using pirate metrics can be useful for tracking and optimising the growth and performance of a product or business.