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Documentation Index

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Lean started on Toyota’s factory floor in the 1950s and took forty years to reach software. The core idea is deceptively simple: identify what creates value for the customer and eliminate everything else. What’s left is a system that flows 🏭

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The five principles

Toyota’s lean system boils down to five principles, still relevant for product teams today:
  1. Define value from the customer’s perspective - not what you think is valuable, what they actually need
  2. Map the value stream - every step that gets you from idea to customer, and identify which steps add value and which are waste
  3. Create flow - remove the bottlenecks and handoffs that cause work to pile up and slow down
  4. Establish pull - work is pulled by demand, not pushed by a schedule. Start new work when there’s capacity, not because the plan says so
  5. Pursue perfection - continuous improvement, always. There is no done state

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Waste in software

In manufacturing, waste is physical - excess inventory, defects, unnecessary motion. In software, it’s less visible but just as real:
  • Features built that nobody uses
  • Work sitting in a review queue for a week
  • Rework caused by unclear requirements
  • Meetings that produce no decisions
  • Handoffs between teams that introduce delays and context loss
Value Stream Mapping (covered in Value Stream Mapping by Karen Marting and Mike Osterling) is the lean tool for making this visible - mapping every step in your delivery process and measuring where time is actually spent 💡

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Lean and agile

Lean is the philosophical foundation that agile methods build on. Scrum, Kanban, and XP are all expressions of lean thinking applied to software. The language differs but the goal is the same: reduce waste, increase flow, deliver value continuously. The Lean Startup extends lean principles into product discovery - the build-measure-learn loop is lean’s pull system applied to validation. Ship the smallest thing that tests your hypothesis, learn, repeat 🙌

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What it means for PMs

Lean thinking gives you a useful lens for any process problem: where is work waiting? Where is effort being spent on things that don’t create value? Where are handoffs causing delay and quality loss? Lesson learned: the most impactful lean exercise I’ve seen in a product team wasn’t a fancy workshop - it was putting sticky notes on a wall for every step between “idea approved” and “feature in production” and timing each one. The waiting time was always the shock.