The CONTROL phase is the conclusion of the team's journey. The GB/BB is responsible for a solid hand-off to the Process Owner to maintain the gains.
The final capability is determined and the closing performance and all related changes are documented on the closing contract. This phase is not as statistically intensive as the MEASURE, ANALYZE, and IMPROVE phases.
Rewarding the team and stakeholders is important because they not only deserve it but to leave on a final positive note and grow credibility for the GB/BB and the company's Six Sigma program.
There can not be enough emphasis placed on the importance of devoting the same high level of energy and commitment throughout this phase. Complacency and anxiety can set in for the sake of bringing closure and receiving some form of closure or credit.
This can result in the process reverting to the former performance levels and loss of some or all of the gains. In addition, the Six Sigma program and the GB/BB lose credibility.
One of the most common complaints of projects are that they are the "flavor of the month". Rigorous follow-up and corrective action with comprehensive yet simple documentation can increase the likelihood that the gains are sustained.
The GB/BB should also make recommendations to upper management or a MBB for future project recommendations to further improve process performance. These can lead to new Six Sigma projects or Kaizen Events.
Below are a list of tools commonly used in this phase.
Once the improvements are complete it
may be warranted to calculate new process control limits and make these
limits the triggers for corrective and preventive action.
If the three questions below can be answered YES then recalculate the control limits of the process and use them on the SPC charts and document them on the Control Plan for future monitoring.
you can not answer YES to all of the above criteria then the Process
Owner should have information in the Control Plan that identifies corrective
action and ideas for the special causes (assignable causes). The
process is probably not mature or in enough control to use recalculated
Process control should be done before assessing final process capability.
Six Sigma Modules
Green Belt Program (1,000+ Slides)
Cause & Effect Matrix
Central Limit Theorem
1-Way Anova Test
Correlation and Regression