n this series we have been looking at the principles of DMAIC. Last issue we decomposed Analyze; this issue we will look at step four, "Improve". In issue 15 we had examined the collection of DMAIC and how they link; now we are gaining knowledge regarding each principle, as individuals.
Step Four: "Improve"
Previously we have examined Define, Measure, and Analyze. As you may recall, the Measure Phase was to collect the expert opinion (tribal knowledge). Everything in Measure is organized to collect all the possible X / Y relationships and to prioritize them. The prioritization depends solely on the opinion of the experts and is accomplished through a system of forced ranking. In the Analyze Phase we prove or disprove what has been learned in "Measure" by subjecting it to statistical logic.
The Six Sigma Improve Phase is where you develop, implement, and evaluate solutions. All the activities leading up to "Improve" did not include active manipulation. The previous steps have been created to assure that when active manipulation begins we are acting on the most useful X / Y relationships. The improvement process, in Six Sigma, relies on favorable impact on the Y's by properly manipulating the X's. In that Y's are outcomes, it is not practical to manipulate Y's to effect change.
The profound and exhaustive examinations of the X / Y relationships that have preceded the Improve Phase assure the practitioner that we are in deed digging in the right location. Other programs may allow you to continue to accelerate the excavation even if you're digging in the wrong spot.
The improvement actions follow many of the traditional methods:
- Consensus building
- Creativity methods
- Additional data collection
- Design of Experiments
- Flow diagrams
- Mistake proofing (Poka-Yoke)
As the X's are manipulated, in order to bring about favorable changes in the Y's, we must continually validate the outcomes. This may require additional statistical monitoring.
The general process for "Improve":
- Review what you know about the process and the verified relationships
- Brainstorm solution ideas using creativity methods
- Combine ideas into solutions
- Implement and generate criteria for evaluation
In the next issue we will take a close look at the "Control Phase"