Page 373 - The Toyota Way Fieldbook

Chapter 15. Complete a Thorough Root Cause Analysis 347

within the ability or responsibility of the person developing them. A critical
thought process of the Toyota Way is the assumption of finding causes that are
in the direct control of the problem solver. In any problem analysis it is always
possible to find causes that originate outside the control of the problem solver.
For instance, it’s common to find fault with a supplier of material, or with a sup-
port group such as maintenance, or engineering (this is jokingly referred to as the
“Five Who’s” and the objective is to find “root blame” rather than root causes).
Also, there is a tendency to accept certain causes as “the way it is,” and therefore
preclude the possibility of change. The following example demonstrates this
phenomenon.
During the analysis of the sawing operation shown in Figure 15-3, it was
determined that clean-up time was resulting in loss of production. The saws
operated for three shifts, and each shift was assigned 30 minutes to clean up,
resulting in a loss of 90 minutes per day. Following the Five-Why chain in Figure
15-2 above it is apparent that the operation is experiencing problems meeting
the daily production requirement. There are lost time opportunities, and there-
fore the goal would be to capture the lost opportunities. The causal chain would
appear as shown in Figure 15-6.
The cleaning activity is the “point of cause.” Finding the point of cause will
provide both the time and place that the problem occurs. At this stage the root
causes have not been determined, and the “Why?” questioning continues.
The leader asks: “Why do we clean up?” to find the root causes.
Likely responses will be:
“It helps safety.”
“It makes the work area look better.”

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)
Why? Why? (Not most significant)
Cycle time losses Process not running
Why?
Clean-up (Point of Cause)
Why?
Leads to root causes
Figure 15-6. Identifying point of cause