Lean Thinking: The Many Flavors of Waste

The seven types of waste are a foundational concept in lean manufacturing, all forms of muda as described by Taichi Ohno of Toyota. Reducing waste systematically can help you achieve flow in your processes. Waste can result from:

  • Overproduction – making too much of something that goes unused, spoils, or collects dust.
  • Inventory – keeping too much of something that goes unused, and costs time or money to store.
  • Extra Processing – wasting time or effort on steps that are unnecessary.
  • Motion – exerting energy to do something that doesn’t create value.
  • Defects – products or processes that don’t conform to their specifications.
  • Waiting – time spent being unproductive could be used in other ways to create value.
  • Transportation – moving things over long distances costs time, effort and money.

In addition to muda, mura (unevenness in production) and muri (overburdening of people and equipment) are also recognized as characteristics of a process that impede flow. Overburdening either people or machines can lead to burnout, which can result in a high repair or replacement cost!


Pydzek, T. (2003). The Six Sigma Handbook: The Complete Guide for Greenbelts, Blackbelts, and Managers at All Levels, Revised and Expanded Edition.

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