Lean teams use DMAIC for complex problems where the cause is not obvious. It pairs well with lean tools in Lean Six Sigma programs. The Control phase helps stop results sliding back.
Where it comes from
DMAIC is the improvement cycle of Six Sigma, which began at Motorola and spread widely afterward. It was later combined with lean methods under the name Lean Six Sigma.
At a glance
The five DMAIC phases
Swipe sideways to see the whole diagram.
How to apply DMAIC
- 1
Define
Write a project charter with the problem, goal, scope and customer requirements. Draw a high-level process map so everyone agrees on the boundaries.
- 2
Measure
Choose the metrics and check that the measurement system is reliable. Collect baseline data on current performance.
- 3
Analyze
Use tools like fishbone diagrams, five whys and statistical tests to find root causes. Confirm causes with data before acting on them.
- 4
Improve
Generate and test solutions that address the confirmed causes. Pilot changes on a small scale and measure the result.
- 5
Control
Update standard work, add control charts and assign a process owner. Hand over a control plan so the gains are sustained.
Worked example
A claims team sees too many applications returned for missing information. Data shows most returns come from two form fields, and analysis traces them to unclear instructions. The team rewrites the form, pilots it and adds a weekly check on the return rate.
Common mistakes
- Jumping to solutions in the Define phase before root causes are confirmed.
- Skipping measurement system checks, so decisions rest on unreliable data.
- Closing the project without a control plan, letting performance drift back.
When DMAIC is not the right tool
DMAIC improves an existing process. Designing a new product or process from scratch often uses DMADV or design for Six Sigma instead.
For a simple problem with a clear cause, a full DMAIC project is more than you need. An A3 or quick PDCA may be enough.
DMAIC steps and the tools in each
Define sets the problem, scope and goal, often in a project charter with a SIPOC diagram. Measure builds a baseline and checks the measurement system. Analyze finds the root causes with tools such as the fishbone diagram, five whys and hypothesis tests.
Improve tests and implements solutions, sometimes with designed experiments or a pilot. Control keeps the gain with a control plan, statistical process control charts and updated standard work.
DMAIC process map
A DMAIC process map lays out the five phases left to right, with a tollgate review between each. Under each phase it lists the main questions and the outputs the review expects, such as the charter after Define or the verified root causes after Analyze.
Teams also map the process they are improving. A high-level SIPOC map in Define is followed by a detailed process map in Measure, which shows where data should be collected.
DMAIC project examples
A hospital lab might use DMAIC to cut the time from sample to result. A call center might reduce repeat calls. A plant might lower the scrap rate on one machine. Each project has a measurable goal, a clear owner and a defined scope. The Six Sigma guide explains how DMAIC fits with the belts and the wider method.
Roles
A sponsor owns the business result and removes obstacles. A Green Belt or Black Belt leads the project and the analysis.
Process owners and team members bring knowledge of the work and own the control plan at the end.
Tollgates
Many programs hold a tollgate review at the end of each phase. The sponsor checks the deliverables before the team moves on.
Operational excellence software often tracks these gates across a portfolio of projects.
| Phase | Typical tools | Output |
|---|---|---|
| Define | Charter, SIPOC, voice of the customer | Agreed problem and scope |
| Measure | Measurement system analysis, baseline capability | Trusted baseline data |
| Analyze | Fishbone, five whys, hypothesis tests | Verified root causes |
| Improve | Designed experiments, poka-yoke, SMED | Tested solution |
| Control | Control charts, control plan, standard work | Sustained result |