Page 369 - The Toyota Way Fieldbook

Chapter 15. Complete a Thorough Root Cause Analysis 343

TRAP
In many cases we see people attempting to force the Five-Why
process into five boxes by trying to “figure out” the correct chain
with five “answers.” This process does not fit a predeveloped
template format. The causal chain may branch at any level and
yield unknown quantities of answers at each. If you are strug-
gling to find Five Whys, most likely you’re jumping across links
in the chain. Take time to reflect on the simpler, more obvious
answer in order to allow the discovery of all possibilities.

the Five Why chain. The first challenge is to focus solely on the direct question:
“Why are the fabrication units per hour below goal?” Then the true answer
would obviously be: “Because we do not make enough parts each hour.”
Knowing where to focus is crucial in order to train our minds to understand the
complete chain. Skipping what appear to be obvious links in the chain will cause
jumping to preconceived causes, thus overlooking other possibilities. This is
one of the greatest risks and also the greatest challenges in thinking.
Proceeding with our questioning, we would ask, “Why don’t we make enough
parts each hour?” Again the tendency is to skip to the obvious answers, but by
approaching this with a different thought process, we would see this answer:
“Because we lose opportunities to make good parts.” The production of any prod-
uct is accomplished by utilizing the time of people and machinery, and available
material. In this case there are only two main causes for a shortage of produc-
tion—loss of time and loss of material (scrap). Note that this line of thinking
also maintains a narrow focus that will isolate the most significant causes from
the less significant ones. In the example above, the first question led immedi-
ately to a lengthy list. Once a long list is established, it’s extremely difficult to
narrow the focus. It is much easier to maintain a narrow focus and divide the
possibilities gradually through effective questioning. At this point the Five Why
chain would look like Figure 15-1.

Problem statement: The fabrication units per hour is below goal.
Why?
We are not able to make enough parts each hour
Why?
We are losing production opportunities
Why? Why?
Losing time Losing parts (scrap)
Figure 15-1. Initial Five-Why analysis