Project Management guide · Project management fundamentals
What Is Six Sigma in Project Management? DMAIC and Belts
Six Sigma is a data-driven approach to improving quality by reducing variation and defects in processes. Developed at Motorola in the 1980s, it uses structured improvement projects led by trained practitioners.
Key takeaways
- Six Sigma reduces variation and defects using data.
- DMAIC improves existing processes; DMADV designs new ones.
- Belts indicate training level and role.
The goal
A process operating at "six sigma" quality produces no more than 3.4 defects per million opportunities. In practice, Six Sigma is less about hitting that number than about using data to understand and reduce variation.
DMAIC: improving existing processes
- Define the problem, customer requirements and project goals.
- Measure current performance.
- Analyse data to find root causes.
- Improve the process by addressing root causes.
- Control the improved process to sustain results.
DMADV: designing new processes
For new processes or products, Six Sigma uses DMADV: Define, Measure, Analyse, Design, Verify. This is often called Design for Six Sigma (DFSS).
Belt levels
| Belt | Typical role |
|---|---|
| Yellow Belt | Basic awareness; supports projects |
| Green Belt | Leads small projects part-time |
| Black Belt | Leads complex projects full-time; coaches Green Belts |
| Master Black Belt | Trains and mentors; guides the programme |
Common tools
- Process maps and SIPOC diagrams.
- Pareto charts and fishbone diagrams.
- Control charts and statistical process control.
- Hypothesis testing and regression.
- Failure mode and effects analysis (FMEA).
Free templates for this topic
Frequently asked questions
Who created Six Sigma?
Six Sigma was developed at Motorola in the mid-1980s, with engineer Bill Smith widely credited, and popularised by General Electric in the 1990s.
Is Six Sigma a project management methodology?
It is a quality improvement methodology delivered through projects, usually following DMAIC.
What is Six Sigma?
A data-driven quality improvement methodology that aims to reduce variation and defects in processes, usually through DMAIC projects.
What does Six Sigma mean?
A process at six sigma quality produces no more than 3.4 defects per million opportunities. The name refers to the statistical measure of variation.
What is DMAIC in Six Sigma?
Define, Measure, Analyse, Improve and Control, the five-step method Six Sigma uses to improve existing processes.
What is DMADV in Six Sigma?
Define, Measure, Analyse, Design and Verify, used to design new processes or products. It is often called Design for Six Sigma.
What are the Six Sigma belts?
Yellow Belt for basic awareness, Green Belt for leading small projects, Black Belt for leading complex projects and Master Black Belt for training and guiding the programme.
What tools are used in Six Sigma?
Process maps, SIPOC diagrams, Pareto charts, fishbone diagrams, control charts, hypothesis testing, regression and FMEA.
What is a SIPOC diagram in Six Sigma?
A high-level process map listing Suppliers, Inputs, Process, Outputs and Customers, often used in the Define phase.
Is Six Sigma still relevant?
Yes, particularly in manufacturing, healthcare, finance and operations, often combined with Lean as Lean Six Sigma. See Lean vs Six Sigma.
Which Six Sigma belt should I start with?
Yellow Belt gives awareness; Green Belt is a common starting point for people who want to lead improvement projects.