5- The Control Tollgate

The fifth and last step is Control. Here a set of tools and techniques are applied to the newly improved process so that the improved sigma performance holds up over time.

There are two major Control Tollgate to the last phase of DMAIC. They are:

1. Determining the technical method of control:

Once improvement has occurred, it is important to make sure that the solutions “stick” over time. The method of technical control is based on how much throughput goes through the new process and how much standardization the new process has.

2. Creating the response plan:

The response plan is similar in appearance to the data collection plan. It chronicles the new process map the team creates as a result of their improvements (called the should-be map):

- The most important measures for the new process

- The specifications and targets as verified by the customers of the process

- What data collection forms are used

- The control methods chosen by the team (in this process, control charts)

- And the most notable process improvements.

5Ms and 1P: Six major factors affecting the performance of the process.

1. Machines in the process.

2. Materials used in the process.

3. Methods in the process.

4. Mother Nature or the environment.

5. Measurement itself.

6. The people.

The technical name when no one factor has an undue influence in the data is common cause variation, because the variation is caused by a common set of variables, the 5Ms and 1P.

nonrandom or special cause are when one or more of the 5Ms or 1P have some undue or special influence on the process.