This document discusses the Lean concept of poka-yoke, which refers to mechanisms designed to prevent mistakes. Poka-yoke implies a method that detects, fixes, and prevents errors as they occur. Examples given include a vehicle brake that must be pressed before shifting out of park to ensure safety, and polarized electrical plugs that prevent shock hazards. The document encourages identifying regular processes, the types of poka-yoke mechanisms in each to prevent what errors, and their effectiveness. It also prompts considering what other errors could be prevented and the potential impact of additional poka-yoke implementations.

1. Section & Lesson #:
Pre-Requisite Lessons:
Complex Tools + Clear Teaching = Powerful Results
Poka-Yoke
Lean – Lesson 8
An introduction to the Lean concept of poka-yoke and how it can be used
to help sustain process improvements.
None
Copyright © 2011-2019 by Matthew J. Hansen. All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted by any means
(electronic, mechanical, photographic, photocopying, recording or otherwise) without prior permission in writing by the author and/or publisher.

2. o What is Poka-yoke?
• A Japanese term meaning “mistake-proofing”.
• It refers to steps, controls or mechanisms designed to prevent mistakes (potential defects).
 It implies a method in the process that quickly and easily detects, fixes and prevents errors as they occur.
• Practical examples of a poka-yoke:
Poka-Yoke
Copyright © 2011-2019 by Matthew J. Hansen. All Rights Reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted by any means (electronic, mechanical, photographic,
photocopying, recording or otherwise) without prior permission in writing by the author and/or publisher.
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Stepping on a vehicle’s
brake pedal before shifting
out of Park (ensures safety).
Polarized AC electrical plugs & sockets
(the bigger side of a two-prong plug –
helps prevent shock hazard).

3. Practical Application
o Identify at least three processes you interact with regularly.
• What are some types of poka-yoke that exist in each process?
 What are the kinds of mistakes or errors that they are trying to prevent?
 How effective are they at preventing those errors?
• What other errors in each process could’ve been prevented if poka-yoke were applied?
 What measurable impact could be realized if that poka-yoke were implemented?
Copyright © 2011-2019 by Matthew J. Hansen. All Rights Reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted by any means (electronic, mechanical, photographic,
photocopying, recording or otherwise) without prior permission in writing by the author and/or publisher.
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