Training, exams and certification
Training, exams and certification
A hundred questions in three hours, closed book, seventy per cent to pass. All five DMAIC phases, roughly twenty questions each — which means the exam tells you, in advance, exactly how to divide your revision.
The IASSC Certified Lean Six Sigma Green Belt exam covers the whole DMAIC cycle, where the Yellow Belt covers three phases of it.
| Questions | 100 graded, multiple choice and true/false. Some forms carry up to 10 additional questions that are not graded |
|---|---|
| Duration | 3 hours |
| Pass mark | 70% |
| Materials | Closed book |
| Prerequisites | None |
| Training | Recommended, not required |
| Project required | No |
| Body of Knowledge | Define, Measure, Analyze, Improve and Control — approximately 20 questions from each |
IASSC publishes the shape of the paper: roughly twenty multiple-choice and true/false questions from each major section of the Body of Knowledge. Five sections, a hundred questions.
| Define | ~20 questions | |
| Measure | ~20 questions | |
| Analyze | ~20 questions | |
| Improve | ~20 questions | |
| Control | ~20 questions |
Nothing is weighted more heavily than anything else, and that is more useful than it sounds. It means the phase you find hardest is worth exactly as much as the one you find easiest, so the efficient revision is flat: bring the weakest phase up rather than polishing the strongest.
It also sets the arithmetic of failure. Seventy per cent of a hundred is seventy, so you can drop thirty questions. Dropping an entire phase — twenty questions — still leaves you ten to spare, but only if the other eighty are close to perfect. In practice, one phase abandoned is one phase too many.
The step up from Yellow is not a step up in difficulty per question. It is two extra phases, and they happen to be the two with the statistics in them.
Analyze brings hypothesis testing, confidence intervals, and the discipline of not concluding more than your data supports. Improve brings designed experiments and the logic of changing one thing at a time.
Candidates who come from a process or quality background usually find Define, Measure and Control familiar and these two unfamiliar. Candidates from a statistical background often find the reverse — and are surprised by how precisely the Body of Knowledge defines terms they thought they already knew.
Three hours across a hundred questions is one minute forty-eight each. Comfortable for a definition, tight for anything you have to work out.
The closed book matters here more than at Yellow Belt, because Analyze and Improve are where you would most want a formula sheet. Whatever the test centre allows you to bring, plan on having nothing.
Revise flat, not deep. Twenty questions a phase means five equal slices of time.
Rehearse the arithmetic by hand. Capability indices, sigma levels, sample statistics — the ones you would normally let software do.
Thirty wrong answers is the margin. Wide enough to survive a bad phase, not wide enough to survive two.
No. There are no prerequisites for the IASSC Green Belt exam.
No. IASSC certifies knowledge through the exam alone.
Approximately twenty from each of the five DMAIC sections.
Three hours for a hundred graded questions.
No. IASSC recommends training but does not require it.
No. Closed book, like the Yellow and Black Belt papers.
Sources. Every figure on this page comes from IASSC’s own published certification pages, checked in September 2026.
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