Tag Archives: mistake proofing

Mistake-Proofing Mistakes

mistakeproofingThere is a popular lore provided by Shigeo Shingo, that the original name for mistake-proofing (Poka-Yoke) was “fool-proofing” (Baka-Yoke). Shingo chided managers at Panasonic for using the latter term, as it was disrespectful to workers, essentially calling them fools. Shingo substituted the word “mistake” for “fool”, because, as he aptly noted, making mistakes is part of humanity. “Mistakes are inevitable,” he said, “but the defects that arise from them are not.”

Notwithstanding Mr. Shingo’s admonitions, however, I still hear the term “fool-proofing” used regularly, and occasionally with a little more venom, “idiot-proofing.”   No doubt, these derogatory terms, along with others like ‘screw-up’ and its less gentile derivatives, have given a bad name to one of the most energizing, empowering and creative tools from the TPS toolbox. Many organizations never even get out the blocks with this technique because of an overt insulting, blame environment. Who wants to report a mistake, when the reward is blame and ridicule? Like Mr. T, managers tend to blurt out the wrong words when mistakes occur. Bad habits die hard.

But even for more enlightened managers there are still some common hurdles to creating a really powerful Poka-Yoke system. A few weeks ago I gave a short Webinar for AME on Poka-Yoke, and was asked this question by a viewer:

“How do I ensure the effectiveness in use of the Poka-Yoke device? People usually don’t want to continue using it.”

Here, with a few embellishments, was my response:

“The general answer to this question from today’s Webinar is that if people don’t find a particular tool purposeful, they don’t use it.  More specifically for poka-yoke, there are seven reasons that the tool is not seen to purposeful by team members:

  1. Sometimes to assure quality, an additional step is added to the operation to prevent or detect the defect, but this step is not considered in the standardized work, i.e., no additional time is allowed.   If the device or method requires an extra step that takes more time (e.g. use of a check list or matching parts to a template) then employees will feel rushed and pressured to choose between rate and quality.
  2. A corollary to the lack of standardized work is the lack of communication to team members, team leaders and managers. An undocumented and untrained standard is not a standard.
  3. If the device or method causes strain to the employee it won’t last. Substituting Muri for Muda is not a good trade off.
  4. For detect-type poka-yoke devices (i.e., a defect is created, but is detected before it can pass to the next operation), the concept involves swarming the defect when it’s trapped in order to understand its root cause. I see many cases where defects are trapped, but there is no follow up. Defects pile up, or they are picked up occasionally by engineering or quality, and no feedback goes back to the production line.  When problems don’t get fixed, this promotes cynicism.  It’s not poka-yoke, just a scrap sorter.
  5. Sometimes, as suggested in the question above, a device is put in place, but the defect persists. This could mean the device isn’t used by the team member, but it can also mean the device just doesn’t work.  More PCDA is needed.   If the device doesn’t work, team members will be the first to know.   Telling them to use something that doesn’t work is disrespectful and disengaging.
  6. The term Poka-Yoke is used too broadly to describe countermeasures that have nothing to do with human error, but relate more to providing proper tooling and fixturing to team members. For example, if a particular job requires super human sensor capability to complete (more Muri), creating fixturing to make the job doable is not a Poka-Yoke solution.   My father, who was a machinist by trade and an artist by avocation, could draw a straight line freehand around an entire room. Most of the rest of us would want a straight edge and a level to complete that task.   The point is when we refer to such countermeasures as “mistake-proofing”, we’re once again disrespecting team members.
  7. Most importantly, if the employee who uses the device is not included in the solution, there is typically little commitment to use it, especially if any of points 1 through 6 apply.

That’s the long-winded answer to the short question.  The short answer to that question is that the “technical” portion of poka-yoke doesn’t work if it is not grounded by a quality culture.”

Perhaps you can think of some other common mistake-proofing mistakes to share with our readers. Please let me hear from you.


By the way, a few years ago, GBMP made a Lean Training DVD about poka-yoke called “Achieving Zero Defects By Respecting Human Nature“. If you’d like to learn more about poka-yoke and how to apply it in your organization, check it out here where you can read about it, view a clip from the video and purchase it if you’d like.

It’s a Small World After All

guestblog[Many thanks to Gerry Cronin and Julieanne Brandolini for passing along the following story about sharing between industry and healthcare.   Gerry manages the Lean Program at the Center for Comparative Medicine (CCM), the Biomedical Research division at the Massachusetts General Hospital, one of the largest programs of its kind in the US.  CCM has been on its Lean journey for 8 years, and has adapted Lean tools and methods in novel ways to service their 5000 customers as efficiently as possible with a staff of 130 employees. As a pioneer in Lean management in Biomedical Research CCM conducts Lean Tours, trainings and seminars to help accelerate the healthcare industry in the development of new therapies against disease. Learn more.]

At GBMP’s recent Northeast Shingo Prize Conference in Hyannis Massachusetts, CCM displayed adaptations of Lean as they have applied it to Biomedical Research  in their Community of Lean Lounge booth.   Conference attendees were drawn in by the wacky display of dangerous animals and props.   But during these times of sharing, CCM staff realized that a majority of the representatives from all different industries shared their frustrations in  getting employees involved with a) active Problem Solving and b) employee engagement. It appeared that everyone – regardless of their work – is faced with the very same challenges when developing a culture of Continuous Improvement. CCM is attempting to address this challenge in novel ways and here is the story that they shared in the Community of Lean Lounge:

Pulling the Cord”

During a Kaizen event that was focused on improving our Gemba Walks, the Team Leads and front-line technicians recognized that many members of our staff were not making the connections of how 5S and problem-solving are integrated into everyday work.  Many still see Lean as “another thing to do”; a “thing” that requires dedicated time for them to find, think, test and implement solutions to problems. The Kaizen Team announced “we are pulling the cord and we need more help to coach our staff to connect the dots”.

“Making it real”

To address this problem, leadership set out to create a realistic life-or-death simulation that would clearly illustrate how 5S, standard work and Problem Solving are part of everyday work.  From this setback was born the “5S Wetlabs”, a portable, 90-minute training session that was designed to reinforce the importance of Standard Work, workplace organization and stakeholder involvement.  During the intense and dramatic simulation, a critical step goes haywire activating an emergency response to save a life.  The “First Responders” encounter a dysfunctional and chaotic situation making the life-saving process totally ineffective, resulting in the tragic death of the victim.  The Responders fail miserably to perform effectively in their role; they articulate feelings of disappointment, of being demoralized, embarrassed and frustrated by their inability to save the victim.

“Shoveling against the tide… or Making Excuses”

The First Responders are asked to list “what went wrong”, which inevitably becomes a shopping list for 5S-related improvements. The Responders are then asked “who killed the victim” and to write an “Obituary” for the victim that will be presented to the family members at the wake.  The Obituary is often comically uncomfortable, forcing the responders to identify “who” and “what” failed, and their contribution to the victim’s death.  The Obituary exercise illustrates how we tend to make excuses, even when we have influence on a process. A short problem-solving session follows which then leads to Responders identifying dozens of improvements that will make the situation fool-proof; especially since every participant now realizes that “they” are the stakeholder.  They are personally relying on the quality and effectiveness of the system for their own survival.  The simulation is then immediately changed and improved, and the students are  challenged to create a system that will save their own lives when the process goes wrong.  5S principals are now demonstrated to the students by transforming a mundane exercise into a realistic life-or-death situation that makes the mistakes painfully personal.

Lean Learning Goes Both Ways

The theme of CCM’s 2013 Lean Lounge booth was “if we can do it, anybody can”.  The 5S Wetlabs display was an instant hit, as it attracted many trainers and managers who were interested in an unconventional approach to teaching the benefits of workplace organization and problem-solving in a short period of time. One such company was a major aerospace manufacturer that had recently experienced system failures that relied on multiple roles. The Continuous Improvement Director instantly saw the value in life-or-death scenario training for engineers and maintenance technicians who develop and maintain machines and processes that can result in death from catastrophic failure.   Other companies that visited the CCM booth expressed interest in the novel approach to personalized training concepts, and many remarked that perhaps the time has come when industry can now learn from healthcare.   While healthcare has been catching up for years, problems encountered in the dynamic healthcare setting can provide useful lessons for all industries when faced with change that threatens the life or death of an organization.  The learning pendulum has shifted, and healthcare may now be the very industry to illuminate the way to rapid improvements in a threatening market or environment.  Can lessons learned from healthcare help your organization?

Notes from O.L.D. :

1)    I think the answer to above question is:  Yes, definitely!  Lean learning is anything but industry specific.  Thanks again to Gerry and Julianne for their story.

2)    It’s not too early to register for our October 1-2, 2014 conference in Springfield, MA. – and maybe sign up for your own  Lean Lounge table. Click here for details.

3)    It’s almost too late to register for my Sign up here for “Tea Time with Toast Dude” – but not quite!  The topic will be “Killer Measures”, traditional measures that can derail your lean implementation.  Hope you can join me on Tuesday, December 10 (tomorrow!) from 3:00 – 3:40 p.m. EST.  Read more & register.