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

been done. It is only necessary to collect actual process data after the change

and chart it in the same way you charted the problem. It should be evident

that if results are going to be presented, it’s necessary to have a baseline for

comparison to verify improvement. It is surprising to discover that in many

cases data priorto “improvement” is not available! How is it possible to veri-

fy improvement if there is no point of comparison? Generally, this is due to

the eagerness to rush off and solve the “problem” without fully understand-

ing the extent. (Without data, the severity of the situation is only a subjective

“feeling.”)

There are two levels of results: those directly related to the root cause being

addressed and those that affect the original problem. If the root causes discov-

ered are part of the correct causal chain, an improvement in results at the root

cause level should travel up the chain using the “Therefore” method and result

in improvement of the original problem, as shown in Figure 17-2.

Chapter 17. Plan-Do-Check-Act 369

TRAP

If the process has been followed correctly, the solutions imple-

mented will produce the desired results. Do not include “results”

that are not related to the problem. For example, a discussion of

improvements to the area lighting would not be relevant to the

problem of not meeting the production requirement. The results

presented must be directly related to the stated problem and the

corresponding indicators.

Problem statement: The fabrication units per hour is below goal. Meet the fabrication units per hour goal!
Why? Therefore
We are not able to make enough parts each hour Produce enough parts each hour
Why? Therefore
We are losing production opportunities Increase opportunities for production
Why? Therefore
Losing time Increase time available
Why? Therefore
Cycle time losses Reduce cycle time losses
Why? Therefore
Loading the machine takes too long Decrease time to load machine
Why? Therefore
Reduce walking
(Solution)

Operator walks 5 feet

for material

(Root Cause)

Figure 17-2. Showing the entire causal chain