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Lean Manufacturing Quality Control and Recalls

Lean Manufacturing Quality Control and Recalls

Quality Control, PDCA, and Recalls

It started with “quality control” systems.  The QC departments were the police of quality, auditing procedures, checking quality and finding guilty parties.  Japanese manufacturers had a different idea:  Quality was everybody’s responsibility and needed to be designed and built in. This approach ideally means giving the customer more then they expect or can even imagine.

Japanese ‘Total Quality Management’ started with Walter Shewhart and his disciple Dr. Edwards Deming. Shewhart created a 3-step quality wheel composed of specification, production, and inspection, where inspection led back to specification. Dr. Deming taught this in Japan where it evolved into Plan-Do-Check-Act (PDCA), another recycling wheel.  The Japanese were culturally comfortable with the uncertainty implied by hypothesis testing and saw the plan as a best guess about what to do until actual experience confirmed the hypothesis, leading to the next hypothesis.

So, how does Toyota’s quality management relate to their infamous 2009-2011 recall crisis? During what seemed to be an endless stream of recalls, there were over 10 million vehicles recalled related to “speed control.” It was widely speculated that these Sudden Unintended Acceleration (SUA) episodes coincided with Toyota shifting to electronic throttle control.

The largest number of vehicles recalled (over 5 million) were because of customer or dealer added all-weather floor mats that could jam the accelerator pedal—a problem other automakers, like Ford, have had since. In Toyota Under Fire, Timothy Ogden and I document that the Toyota floor mats were in fact not defective. The most highly publicized accident, leading to the tragic death of four people, was actually caused by a Lexus dealer placing an unsecured, oversized, all-weather floor mat into a loaner vehicle.

Does this imply massive quality control problems within Toyota?  Even if the all-weather mat was a Toyota defect it would be a single defective design with one known accident. This case seems to indicate that a sensationalized event leads the general public to assume major underlying problems.  In the years since, an unusual numbers of recalls at Toyota mainly came from a policy change to recall first and investigate later to be ultra conservative about safety.

These problems led to a major series of PDCA exercises within Toyota, despite the fact their data did not reveal any increase in objective quality defects. Toyota defined the problem as: We have focused principally on defect-free products from an engineering viewpoint and paid too little attention to customer-perceived quality. One of the main causes of this was the concentration of engineering decision-making in Japan, including decisions about recalls.  Sometimes recalls must take into account the local socio-political environment, which is better understood by local Toyota officials. 

Many countermeasures were put in place as a result of these events, including decentralizing certain powers to local regions, adding time to the engineering development cycle to focus on subjective quality issues, streamlining the process of getting customer concerns to the right engineers, making the North American R&D center more autonomous in decisions about North American cars, initiating new training for field quality specialists, and many more.  In addition, the Toyota Global Vision 2020 emphasizes “…constant innovation, and respect for the planet, we aim to exceed expectations and be rewarded with a smile.”

Despite what many perceived as signs that Toyota’s Quality Control program was losing strength, the recent Toyota recalls and their corresponding responses are actually signs of a well-functioning quality control system.

Click here to listen to Dr. Liker’s interview with Lean Blog about the recalls
Read more about the Toyota recall and the lean movement

Dr. Jeffrey Liker is professor of industrial and operations engineering at the University of Michigan and author of The Toyota Way.  He leads Liker Lean Advisors, LLC and his latest book (with Gary Convis) is The Toyota Way to Lean Leadership