What is Six Sigma?
Six Sigma, developed at Motorola and made famous by GE, uses statistics to find and remove the causes of defects and variation. “Sigma” is a measure of variation; a six-sigma process is extremely consistent.
Projects are led by trained practitioners — Yellow, Green and Black Belts — and follow a structured method called DMAIC.
The DMAIC method
- Define — the problem, the customer and the goal (e.g. cut billing errors by 50%).
- Measure — collect data on the current process and its defect rate.
- Analyse — find the root causes using data, not opinions.
- Improve — test and implement solutions that remove those causes.
- Control — standardise and monitor so the gains stay.
Six Sigma example
A distributor had 6% of invoices disputed. Measurement showed 70% of disputes came from manual price entry for three customer groups. Automating price lookup and adding a check at dispatch cut disputes to under 1%.
Common mistakes to avoid
- Starting projects without reliable data.
- Choosing problems too big to finish in 3–6 months.
- Skipping the Control phase, so the process drifts back.
How DOOfy helps
Six Sigma starts with good measurement. AIMOS One keeps process data — errors, returns, delays, complaints — in one place over time, which makes the Measure and Control phases far easier and shows when a process starts drifting.
Frequently asked questions
What does DMAIC stand for?
Define, Measure, Analyse, Improve and Control — the five phases of a Six Sigma improvement project.
What is the difference between Lean and Six Sigma?
Lean removes waste and speeds up flow; Six Sigma reduces variation and defects. Lean Six Sigma combines both.