Training, exams and certification
Training, exams and certification
Sixty questions in two hours, closed book, seventy per cent to pass. And a detail almost nobody mentions: the Yellow Belt is not a smaller Green Belt. It covers three of the five DMAIC phases, and leaves two out entirely.
The IASSC Certified Lean Six Sigma Yellow Belt exam is an independent knowledge test: IASSC accredits training providers but does not deliver training itself.
| Questions | 60 graded, multiple choice and true/false. Some forms carry up to 6 additional questions that are not graded |
|---|---|
| Duration | 2 hours |
| Pass mark | 70% |
| Materials | Closed book |
| Prerequisites | None |
| Training | Recommended, not required |
| Project required | No |
| Body of Knowledge | Define, Measure and Control — the DMC phases |
The non-graded questions are worth knowing about in advance. If you count sixty-six questions on the screen and expected sixty, nothing has gone wrong: some forms include unscored items that IASSC is trialling for future papers.
Green Belt and Black Belt both cover the full DMAIC cycle. Yellow Belt covers Define, Measure and Control — and stops there.
| Define | Examined |
|---|---|
| Measure | Examined |
| Analyze | Not in the Yellow Belt Body of Knowledge |
| Improve | Not in the Yellow Belt Body of Knowledge |
| Control | Examined |
That shape tells you what the credential is for. A Yellow Belt is someone who can frame a problem, measure it honestly, and hold a gain in place once somebody else has made it. The statistical middle of Six Sigma — hypothesis testing, regression, designed experiments — is Green Belt territory.
It also tells you where to spend your revision. Two hours for sixty questions is two minutes each, which is generous; the difficulty is not the clock, it is that a third of the material people associate with Six Sigma will not appear at all, and the three phases that do appear are examined more closely than candidates expect.
IASSC certifies knowledge, not a project. There is no project submission, no affidavit and no sponsor sign-off — you sit an exam and you either pass it or you do not. That is the clearest difference between the IASSC scheme and the ones that require a delivered improvement before they will certify you.
Whether that makes the credential more or less valuable depends on what you want it for. As evidence that you have read and understood the Body of Knowledge, it is exactly as good as the exam is. As evidence that you have improved a real process, it says nothing, and an interviewer who knows the schemes will know that.
Study the Body of Knowledge, not a generic Six Sigma course. The exam is written against the published document, and the published document is what defines the three phases.
Do not revise Analyze and Improve. They are not examined at this level. The time is better spent on measurement system analysis and process capability, which are.
Two minutes a question, closed book. No formulas sheet, no notes, no calculator policy to rely on — check what the test centre allows before the day.
No. IASSC states that training is recommended but not required, and there are no prerequisites for the exam.
No. The IASSC scheme certifies knowledge through an exam; there is no project submission.
Two hours for sixty graded questions.
Some exam forms include up to six additional questions that are not graded.
Define, Measure and Control. Analyze and Improve are not in the Yellow Belt Body of Knowledge.
No. All three IASSC belt exams are closed book.
Sources. Every figure on this page comes from IASSC’s own published certification pages, checked in September 2026.
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