Toyota Way Fieldbook : A Practical Guide for Implementing Toyota's 4Ps

It may helpful to think of these relationships in terms of the problem, symp-
toms of the problem, and the causes of the problem.
Using a medical condition as an analogy: Suppose you visit the doctor and
complain of aches and fever. These are not the problem. They are symptoms of
the problem. The problem is that you don’t feel well (and as a result may miss
work or other activities). The doctor will take information and perform tests
and gather facts (vital signs) that are part of the analysis, to find the cause of the
aches and fever. Visually, the process looks like Figure 14-2.
Symptoms are presented to the side of the problem, as in “I have this problem,
and as a result I have these symptoms.” To get to the cause(s), the information
is analyzed to evaluate all possibilities. The symptoms are an important piece in
the overall understanding of the problem. They provide supporting evidence
that a problem exists. They also provide quantifiable data showing the magnitude
of the problem. In this case, a fever of 104 degrees is more significant than a
fever of 100, thus increasing the need to treat the problem.
The relationship of the three primary measures will follow the same model
of Problems, Symptoms, and Causes, as shown in Figure 14-3.
In this case, low productivity would be the problem, poor quality a cause, and
high cost a symptom or result. Using this model is important because it forces con-
sideration of the bigger picture. We may believe that a repetitive quality problem

Chapter 14. Develop a Thorough Understanding 329

PROBLEM

(Don't feel well)

AS A RESULT OF

THE PROBLEM

THESE

SYMPTOMS

EXIST

(Aches and Fever)

ROOT CAUSES

ANALYSISLEADS TO

Figure 14-2. Illness symptoms versus root causes