DMAIC (Define, Measure, Analyse, Improve, Control)
DMAIC is a data-driven improvement cycle used to improve, optimise and stabilise business processes and designs. It’s the core process behind many Six Sigma projects—but DMAIC is not exclusive to Six Sigma and can be used as a general framework for structured improvement.
DMAIC process flow
DMAIC abbreviates the five improvement steps: Define, Measure, Analyse, Improve and Control. All steps are required and proceed in this order.
Define
Capture what you know now, clarify facts, set objectives and form the project team. Define:
- A clear problem statement
- The customer(s)
- Critical to Quality (CTQs) — key process outputs
- The target process and related business processes
- Project targets
- Project boundaries
A project charter is often created and agreed during the Define step.
Measure
Plan data collection and verify that your measurement system is fit-for-purpose—good data sits at the heart of DMAIC:
- Define critical inputs (Xs) and outputs (Ys)
- Create a measurement plan
- Test the measurement system
- Collect baseline data
A Measurement System Analysis (gauge study) is performed at this stage.
Analyse
Analyse the data gathered in Measure to determine root causes of defects and sources of variation. Use simple or advanced tools as appropriate:
- Identify gaps between current and target performance
- Understand how inputs (Xs) affect outputs (Ys)
- List and prioritise improvement opportunities
- Identify key sources of variation
Explore data location and spread with histograms and box plots.
Improve
Develop solutions to remove root causes and prevent recurrence. Use brainstorming techniques (e.g., Six Hats, Random Word). Some projects may use DOE, but prioritise straightforward wins when they exist:
- Create innovative solutions
- Favour the simplest, easiest viable options
- Assess risk and robustness with FMEA
- Build a detailed implementation plan
- Deploy improvements
Ishikawa diagrams can be useful across all DMAIC stages and particularly during solution brainstorming.
Control
Monitor improvements to ensure they hold. Create a control plan, then update procedures, process documentation and training as required.
Control charts are often used during the Control stage.
Replicate
Beyond the core five steps, consider replication. Apply successful changes to similar processes and share lessons learned across the organisation.