DMAIC explained: the five phases of a Six Sigma project

Define: what problem, for whom, and why now?

Define sets the project's boundaries: the problem statement, the customer and what they consider critical to quality, the scope, and the business case. A project charter and a high-level SIPOC (suppliers, inputs, process, outputs, customers) map are typical outputs.

Measure: how big is the problem, really?

Measure establishes a trustworthy baseline. The team defines how the output will be measured, checks that the measurement system itself is reliable (for example with a gauge R&R study), collects data, and calculates current process performance.

Analyze: what is actually causing it?

Analyze moves from symptoms to verified root causes. Tools such as cause-and-effect (fishbone) diagrams, process maps and hypothesis tests help the team separate the few causes that matter from the many that do not.

Improve: what change fixes the cause?

Improve develops, tests and implements solutions aimed at the verified root causes. Designed experiments, pilots and risk assessments such as FMEA help confirm the change works before it is rolled out.

Control: how do we keep the gain?

Control makes the improvement stick: a control plan, standardized work, and statistical process control charts that show when the process drifts. The project closes by handing ownership back to the process owner.

• Define: charter, scope, voice of the customer.
• Measure: baseline, measurement system analysis.
• Analyze: verified root causes.
• Improve: tested solutions.
• Control: control plan and monitoring.