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 (illustrative)
A claims team finds that 18% of applications come back for missing information. In Measure, a sample of 400 returned forms shows that about 7 in 10 trace to two fields. In Analyze, the team traces both to unclear instructions. In Improve, it rewrites the two fields and pilots the new form for a month, and returns fall to about 7%. In Control, the process owner gets a weekly check on the return rate, so a slide back shows up early.
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 process map
A DMAIC process map lays out the five phases left to right. Under each phase it lists the main questions and the outputs the next tollgate 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.
From voice of the customer to CTQs
The Define phase starts from the voice of the customer (VOC): complaints, surveys, interviews, support tickets and returns. Those comments are rarely measurable as they stand, so the team turns each one into a critical to quality requirement (CTQ) with a number attached.
Voice of the customer
“Delivery is too slow.”
Slow can mean several different things, and each one leads to a different project:
CTQ: Response time
How long until the order is confirmed.
CTQ: Lead time
How long from order to delivery.
CTQ: Reliability
How often the delivery lands on the promised date.
CTQ: Updates
Whether the customer knows where the order is.
Asking customers which one they mean, and checking the complaint data, picks the CTQ. An illustrative result: 95% of orders delivered by the date promised at the time of ordering. That is a target the Measure phase can check.
| 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 |
Guides on this topic
- Lean vs Six Sigma: differences, history and when to use eachLean vs Six Sigma compared: what each method targets, where they came from, how they differ in manufacturing and how Lean Six Sigma combines them.Read the guide
- How to write an A3 report: step by step, with an exampleHow to write an A3 report section by section, with a worked A3 example and the coaching questions that turn A3 problem solving into learning.Read the guide
- Kaizen event: meaning, steps and a 3-5 day agendaA kaizen event is a focused workshop that improves one process in 3-5 days. Learn the meaning, roles, agenda, steps, measures and common mistakes.Read the guide
- Process improvement methodologies: 9 methods comparedProcess improvement methodologies compared: PDCA, lean, kaizen, Six Sigma, TQM, theory of constraints, BPR and retrospectives, with how to choose and combine.Read the guide
Sources
Books and papers show their publication year. Web pages show the month we last checked them.
- 1.Thomas Pyzdek and Paul A. Keller, The Six Sigma Handbook, 4th edition (McGraw-Hill, 2014)
- 2.ISO, ISO 13053-1: Quantitative methods in process improvement, Six Sigma, Part 1: DMAIC methodology (International Organization for Standardization, 2011)