Page 398 - The Toyota Way Fieldbook

Chapter 17. Plan-Do-Check-Act 371

Act: Make Necessary Adjustments to
Solutions and to the Action Plan

As you can see, the entire problem-solving process is a continuous progression
of developing a hypothesis, testing the hypothesis, measuring results, adjusting
the hypothesis, retesting, measuring, and so forth, until the desired result is
achieved. With continued practice, skills are improved and the first-time suc-
cess rate will be increased. With a thorough understanding of the root causes,
and the contribution of each to the overall problem, the effect of proposed coun-
termeasures is easily predicted. Experimentation and simulation of counter-
measures provide a clear understanding of the effectiveness of proposed solu-
tions prior to any major investment of time or resources.
During this important phase it’s critical to “stand in the circle” and observe
the changes that have been implemented. Watch closely to verify that they pro-
duce the desired result. It is not uncommon for a solution to create new “prob-
lems.” Sometimes these are related to people getting accustomed to the new
method, and it’s important to be able to distinguish “adjustment issues” from
real issues. In some cases the core problem is broken into several smaller pieces,
and lesser problems surface. Continue to address these subproblems until the
operation runs smoothly. (Don’t try to eliminate all problems, since that is
unlikely and you could work toward that goal for a lifetime!)

TRAP
Confusing Problem Solving with Statistical Analysis
When we describe the scientific method of hypothesis, measure-
ment, and testing . . . what will immediately come to mind for some
readers is six sigma. Certainly the DMAIC methodology of six sigma
is very compatible with PDCA and the problem solving method we
describe here. But we have seen six sigma in the hands of novices
become an exercise in statistics instead of an exercise in thinking. The
problem is not well defined, months are spent carefully analyzing
the wrong data, there is little go-and-see activity, and the solutions
are simplistic or just plain wrong. The Toyota Way focuses on facts,
most often in their purest and simplest form. As Mark Twain once
said: “Facts are stubborn things, but statistics are more pliable.”

Act: Identify Future Steps

The successful completion of a problem-solving activity should be celebrated and
the efforts of everyone involved recognized. Members are to be congratulated on
their ability to effectively identify the problem causes and for their creativity and