Definition
The Lean Startup is a methodology for building startups and new products, synthesized by Eric Ries from three pillars: Steve Blank's Customer Development, agile software development, and lean manufacturing concepts. Ries published the methodology in "The Lean Startup" (2011), which became a New York Times bestseller and the most widely read articulation of the approach.
The Three Pillars
1. Customer Development (Blank): The process for validating business models through direct customer contact 2. Agile Development: The engineering methodology for iterative, incremental product building 3. Lean manufacturing concepts: Adapted from Toyota Production System — eliminating waste, iterating rapidly, measuring what matters
Key Additions by Ries
Ries added several concepts that extended Blank's framework:
Minimum Viable Product (MVP): The smallest product that allows a team to collect the maximum amount of validated learning with the least effort. MVPs are designed to test specific hypotheses, not to impress customers.
Build-Measure-Learn loop: The fundamental feedback loop — build an MVP, measure how customers respond, learn whether to persevere or pivot. This is the operational cycle that implements Customer Development at the engineering level.
Validated learning: A unit of progress for startups that replaces traditional metrics (revenue, profit, market share) which are premature and misleading for early-stage ventures.
Innovation accounting: A framework for measuring progress when traditional accounting metrics do not apply. Uses actionable metrics (conversion rates, engagement) rather than vanity metrics (total users, page views).
Blank-Ries Relationship
The relationship is explicitly one of intellectual transmission: Blank was Ries' teacher, investor, and advisor. Ries copyedited an early version of "Four Steps" and applied Customer Development at IMVU. The Lean Startup synthesizes Blank's strategic framework with engineering practice, making it actionable at the product development level. Ries published his synthesis in "The Lean Startup" (2011), which became a New York Times bestseller and the most widely read articulation of the methodology.
Both Blank and Ries have acknowledged that the OODA loop from Boyd's work provides a structural parallel to the iterative cycles in their frameworks, though this was a retrospective recognition rather than an originating influence.
Significance
The Lean Startup methodology transformed the startup ecosystem — changing how ventures are funded, how products are built, and how entrepreneurship is taught. Its influence extends beyond startups into corporate innovation (lean enterprise), government (I-Corps, GovTech), and nonprofit/social enterprise. It is the most widely adopted practical framework to emerge from Blank's Customer Development methodology.