Page 124 - How To Implement Lean Manufacturing

How to Do Lean—Cultural Change Fundamentals 103

6. Why does our management ask questions about yield and production and
not quality?
• Because management is more interested in yield and production than
they are in quality (solution statement).
A couple of points about the 5 Whys
• First, the 5 Whys technique is seldom a straight line-linear process. For
example, you will note that the second “Why?” has five possible answers
and we only addressed one of them. We have two options when we have
multiple causes.
• We could answer why to each of these, which would give us a very
branched problem solution. Quite frankly, all five branches might
converge on the same conclusion.
• However, the normal advice is to quantify the issues and follow the
branch with the largest impact.
• Second, as is the case here, it is arguable if you have reached a root cause,
which is the objective of problem solving. For example, why is management
more interested in production than quality? Maybe it’s because of their
bonus structure, or just maybe it’s the best thing for the company today.
Nevertheless, with problem solving of human systems, often the root
cause is not really found, and sometimes it isn’t necessary. What is
necessary is to find an “actionable cause that reasonable people agree
should be changed?”

Let’s check this possible solution statement with the “therefore” technique. If “man-
agement is more interested in yield and production than they are in quality” is a good
answer to our problem, then the “therefore” technique will logically connect the “Whys”
in reverse order, starting with the solution statement.

An example of the “Therefore Technique,” which is a check of the 5 Whys.
Management is more interested in yield and production than quality (the solu-
tion statement).

1. Therefore, the questions we get from management focus on production and
yield, not quality
2. Therefore, we only need total reject data to answer these questions.
3. Therefore, the data are total reject data only and not stratified by defects.
4. Therefore, the data are not good enough for solving quality problems.
5. Therefore, quality problem solving, an integral part of jidoka, is hard to do.
6. Therefore, jidoka is a weakness in Lean implementations.
And it works, which tends to confirm the validity of our solution statement.