Lean Six Sigma training
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IASSC Certified Lean Six Sigma Black Belt (ICBB) Exam Guide
Validates advanced knowledge of the DMAIC method, including regression, designed experiments and statistical tools for Lean Six Sigma.
The exam checks that you can choose and apply the right tool at each DMAIC phase, with a heavy share of statistics, including regression, hypothesis tests on normal and non-normal data and designed experiments. It is closed book, so you need to know which test or chart fits a situation without looking anything up.
Understand the exam
Syllabus
IASSC draws about 30 questions from each of the five phases (150 scored in total).
1.0Define phaseAbout 30 questions
- 1.1The basics of Six Sigma
- 1.2The fundamentals of Six Sigma
- 1.3Selecting Lean Six Sigma projects
- 1.4The lean enterprise
2.0Measure phaseAbout 30 questions
- 2.1Process definition
- 2.2Six Sigma statistics
- 2.3Measurement system analysis
- 2.4Process capability
Example scenario: A gauge study shows that most of the variation in readings comes from different operators measuring the same part. Which part of the measurement system is the problem, and what would you do first?
3.0Analyze phaseAbout 30 questions
- 3.1Patterns of variation
- 3.2Inferential statistics
- 3.3Hypothesis testing
- 3.4Hypothesis testing with normal data
- 3.5Hypothesis testing with non-normal data
Example scenario: You compare three machines on a skewed output measure with small samples. Which test fits, which assumption rules out one-way ANOVA, and how do you read the p-value?
4.0Improve phaseAbout 30 questions
- 4.1Simple linear regression
- 4.2Multiple regression analysis
- 4.3Designed experiments
- 4.4Full factorial experiments
- 4.5Fractional factorial experiments
Example scenario: You can run only 8 trials to test 4 factors at two levels each. Which design fits, what does its resolution tell you about confounding, and what do you give up?
5.0Control phaseAbout 30 questions
- 5.1Lean controls
- 5.2Statistical process control (SPC)
- 5.3Six Sigma control plans
Example scenario: You want to detect a small, sustained shift in a process mean quickly. Which control chart suits that better than a standard Xbar chart, and what is its trade-off?
Official IASSC Black Belt Body of Knowledge · BoK v3.2
Format
- Questions
- 150
- Duration
- 4h
- Passing score
- 70%
- Delivery
- Test centre or online
- Languages
- English, French, Japanese, Spanish
Question types
Read a short scenario or data summary and choose the one correct answer from the options.
CertUp example
You compare mean cycle time across three machines. The data are roughly normal with equal variances. Which test fits?
Show answer
One-way ANOVA. It compares the means of three or more groups when the data are roughly normal with equal variances.
Read a statement and decide whether it is true or false.
CertUp example
True or false: a Pareto chart ranks causes so you can see which few account for most of the problem.
Show answer
True. A Pareto chart orders categories by size, which shows where fixing a few causes removes most of the defects.
Eligibility and booking
Buy an on-demand voucher, then schedule your exam. For the online route, an IASSC proctor meets you in a virtual testing room, checks your ID by webcam and stays with you through the exam. IASSC also lists test centres and accredited providers.
Make a study plan
Read the Body of Knowledge and try the Evaluation Exam first, so you can see which phases are weakest. Spend most of your time on the sections where you score lowest, which is often the statistics.
Most candidates spend 60–120 hours. Plan for the low end if you use regression and designed experiments every week; add time if hypothesis testing or DOE are new to you.
- 1Understand the examRead the syllabus and format, check you’re eligible and pick a target date.5 h
- 3Learn the core conceptsWork through one main course or book, topic by topic.60 h
- 4Practice with mock examsTake timed practice tests and review every mistake.30 h
- 5Prepare for exam dayBook the exam and check the ID and delivery rules.5 h
Learn the core concepts
Use the free Body of Knowledge as your syllabus and pick one main course or book that follows it.
Best video courseCertified Lean Six Sigma Black Belt Training (Accredited)
Best live instructionLean Six Sigma Black Belt Certification Training
Best ebookCertified Lean Six Sigma Black Belt EbookLearn the process, not a toolbox. Link each tool to the DMAIC phase that uses it and the tool that feeds it, rather than memorizing a list.
Practice with mock exams
IASSC’s own Evaluation Exam is the closest practice. Use it to find weak phases, then retake it after studying.
Free Lean Six Sigma Black Belt Practice Test
IASSC Black Belt Evaluation Exam
Lean Six Sigma Black Belt (ICBB) Mock ExamAre you ready?
- You can choose the right hypothesis test, normal or non-normal, for a scenario.
- You can pick a regression or factorial design and say what it can and cannot tell you.
- You can explain why each wrong option in a practice question is wrong.
- You score consistently above the 70% pass mark on Evaluation Exam retakes.
Prepare for exam day
The exam is closed book. Follow the checklist for your delivery route.
Before testing with online proctoring
Before testing at a centre or accredited provider
- Run the compatibility check at least 24 hours ahead on the same computer, network and room, and again about two hours before the exam.
- Show the same valid, original, government-issued photo ID you used to book; a name mismatch means no test and no refund.
- Use a private room with one visible doorway and a clear desk, and be ready for a 360-degree camera scan.
- Close chat, screen-sharing and virtual machine software, and turn off browser extensions, including AI and translation tools.
- Use a computer with a working webcam; a phone cannot replace it.
- Book the centre or accredited provider that delivers IASSC exams in your area.
- Bring the same photo ID you used when booking, matching your name exactly.
- Bring no notes or reference material; the exam is closed book.
Advice from exam takers
A dedicated exam book can help.
A passer who passed the Black Belt on a first attempt in July 2026 credits a Black Belt exam-prep book, saying it explained concepts logically and had question difficulty close to the real exam. They add that IASSC recertification is a drag compared with CSSC, which does not require it.
Study the whole process.
A commenter who recommends an IASSC accredited provider’s materials warns that most training teaches a toolbox of tools without how the overall process works or how the tools feed each other.
The exam is the whole certification.
Commenters confirm that you are an IASSC Certified Black Belt when you pass the exam, with no project side. A project requirement comes from a training provider, not from IASSC.