The same thing happens in our organizations too. We come up with better ways of doing things, they work well for a while, then we slip back into our old way of doing things. As someone once said, "old habits die hard." The founders of the DMAIC process must have realized this and placed the control phase at the very end.
The purpose of control is simple: once the improvements have been made and the results are documented, continue to measure the process routinely, adjusting its operation when the data indicates you should do so or when the customer's requirements change. The key to making this happen is to have a good process management plan in place.
A good process management plan contains four elements -- an updated process map, action alarms, approved back-up plans, and continuous improvement plans.
- Current process map. A concise process map provides a visual aid so a supervisor or manager can see at a glance the flow of activities and decisions in a process.
- Action alarms indicate thresholds and lets the process owner know when to take action. For example, the failure to complete three customer orders on time may signal the need to go to a contingency plan for deliveries.
- Approved back-up plans spell out what employees need to do if something goes wrong so they aren't forced to make hasty decisions.
- Continuous improvement. By tracking the occurrence of problems in the process, process owners will have the information and data to allow overhaul of the weak parts of the process.
Without control efforts, your improved process may very well revert to its previous state, undermining the gains you achieved and making all your hard work for naught!