Getting to the root cause of a quality problem

by Renaud Anjoran on January 28, 2010

The root cause is what must be addressed to eliminate any quality problem. Getting to the root of a quality problem is seldom the concern in Chinese factories. They prefer to point fingers, and find responsible people.

The China method: the “5 whos”

There is no concern about the root causes of problems. The short-term mentality focuses attention on quick fixes, and often on finding mistakes. Here are just a few real-life quotes:

Workmanship is not good? The operator did not pay enough attention, so she will have to repair it. Next time she should be fired.

The products are not conform to the blueprints you gave us? But, you know, the customer’s designers don’t really know how production works.

We will miss the deadline for shipping? Our factory has bad feng shui!

Actually the concept of “root cause” itself has not made its way in most Chinese factories. It is an education problem, not just an attitude problem.

The Toyota method: the “5 whys

According to Taiichi Ohno, asking why repeatedly is “the scientific basis of the Toyota system”. It has lead Toyota to make all sorts of improvements. How? By addressing systematically the root cause of each obstacle they found, on their route to cuts total costs.

Ohno gives a great example of the “five whys”: let’s say a machine has stopped functioning and one needs to get to the root cause:

  1. Why did the machine stop?    -There was an overload and the fuse blew.
  2. Why was there an overload?    -The bearing was not sufficiently lubricated.
  3. Why was it not lubricated sufficiently?    -The lubrication pump was not pumping sufficiently.
  4. Why was it not pumping sufficiently?    -The shaft of the pump was worn and rattling.
  5. Why was the shaft worn out?    -There was no strainer attached and metal scrap got in

I wish more Chinese managers (and if possible line workers) were trained to think this way… It would be a gigantic step in the right direction!

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{ 2 comments… read them below or add one }

Dan January 29, 2010 at 5:03 am

Not a good time to be holding up Toyota as the pinnnacle of quality control!

Renaud Anjoran January 29, 2010 at 9:14 am

Yes, good point… They USED to be the absolute reference. Somehow they have slipped from the principles that led them to greatness.

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