DMAIC: The Five Phases Explained for CPHQ

DMAIC is the structured problem-solving methodology at the heart of Six Sigma. The CPHQ exam tests your knowledge of each phase and the tools used within them. DMAIC stands for Define, Measure, Analyze, Improve, and Control.

Define Phase

The Define phase establishes the scope and goals of the improvement project. Key activities include developing a project charter, identifying the problem statement, defining the scope, establishing team roles, and creating a SIPOC diagram. The project charter should include a clear problem statement, goal statement, business case, timeline, and team members. A well-defined problem is specific, measurable, and focused on the gap between current and desired performance.

Measure Phase

The Measure phase establishes baseline performance and validates the measurement system. Activities include developing a data collection plan, validating measurement systems, collecting baseline data, and creating process maps. Key tools include operational definitions, data collection forms, process capability analysis, and measurement system analysis (MSA). The goal is to quantify the current state with reliable data before attempting to identify root causes.

Analyze Phase

The Analyze phase identifies root causes of the problem. Tools include cause-and-effect diagrams, hypothesis testing, regression analysis, failure mode and effects analysis, and the "5 Whys" technique. This phase moves from potential causes to verified causes using data analysis. The output is a validated list of root causes that the team will address in the Improve phase.

Improve Phase

The Improve phase develops, tests, and implements solutions. Activities include generating potential solutions, selecting the best solutions using criteria matrices, piloting changes on a small scale, and implementing the validated solution. Solutions should target the verified root causes identified in the Analyze phase.

Control Phase

The Control phase ensures that improvements are sustained over time. Key tools include control charts, standard operating procedures, training plans, and control plans. The goal is to hand off the improved process to process owners with monitoring systems in place to detect any degradation in performance. This phase is critical because many improvement gains are lost without proper controls.