Lean Six Sigma Green Belt (IASSC ICGB)
IASSC (International Association for Six Sigma Certification)
Complete guide to passing the Lean Six Sigma Green Belt (IASSC ICGB) exam on your first attempt.
$350-$402
Not published
Recognised perpetually; Current status lasts 3 years
Global
IASSC (International Association for Six Sigma Certification)
$102k-$172k
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Complete Overview
The IASSC Certified Lean Six Sigma Green Belt (ICGB) is the Green Belt credential issued by the International Association for Six Sigma Certification, and it is the exam most people mean when they search for Lean Six Sigma Green Belt certification by that exact name. The exam is 100 multiple-choice and true or false questions, closed book, proctored, with a three hour time allowance and a minimum passing score of 70 percent. IASSC lists the Green Belt exam at 350 USD on its certification pages, while the IASSC order store lists the Green Belt On-Demand Web-Based Certification Exam Voucher at 402 USD.
This page describes the IASSC credential specifically. It is a different certification from the ASQ Certified Six Sigma Green Belt (CSSGB), which is issued by the American Society for Quality, runs 110 questions over 4 hours and 18 minutes, costs 483 USD with 283 USD retakes, and requires three years of full-time paid work experience in one or more areas of the ASQ Body of Knowledge. IASSC sets no prerequisites at all: any candidate can buy a voucher and sit the exam without training, experience or a completed project.
The IASSC Green Belt Body of Knowledge is organised into five phases: Define, Measure, Analyze, Improve and Control. IASSC states the exam contains approximately 20 questions from each major section, which puts each phase at roughly 20 percent of the 100 questions. Some exam forms carry up to 10 additional non-graded questions on top of the 100. Content ranges from Y equals f of x problem framing, DPU, DPMO, FTY, RTY and cost of poor quality in Define, through SIPOC mapping, FMEA, gage repeatability and reproducibility and process capability in Measure, into hypothesis testing with normal and non-normal data in Analyze, simple and multiple regression in Improve, and statistical process control charts, kanban, poka-yoke and control plans in Control.
IASSC targets a cognitive level up to Evaluate on the revised Bloom taxonomy for Green Belt exams, one level below the Create target used for Black Belt. In practice that means candidates are asked to judge which tool or test fits a described situation rather than to design a full improvement programme.
Testing runs through more than 8,000 testing centres in 165 countries, through the PeopleCert Online Proctoring system 24 hours a day, and through IASSC Accredited Providers. A non-programmable four function or scientific calculator is permitted. Graphing calculators, programmable calculators, phone calculators and statistical software such as Minitab and SigmaXL are not permitted. IASSC supplies a reference document that becomes available as a download during the startup steps of the exam session, and candidates are told not to bring their own copy.
IASSC recognises certifications perpetually and indefinitely, but since 1 March 2017 it applies a status classification on top of that. A certification holds Current status for three years from the last day of the month in which it was earned, then moves to Elapsed unless the holder recertifies. The Green Belt recertification exam is 50 questions in 1.5 hours at 70 percent, listed at 175 USD on the recertification page and 268 USD in the IASSC store, limited to two attempts at least two weeks apart, and it must be taken no later than 90 days after the elapse date.
Why Get Lean Six Sigma Green Belt (IASSC ICGB) Certified?
No prerequisites: IASSC requires no training, no work experience and no completed project to sit the Green Belt exam.
The exam is 100 questions in 180 minutes, which gives 108 seconds per question, and true or false items clear far faster than that, banking time for the Analyze calculations.
Each of the five DMAIC phases supplies about 20 questions, so a candidate who ignores one phase gives up about 20 percent of the paper.
The pass mark is a flat 70 percent, so 70 correct answers out of 100 clears it with no scaled-score conversion to interpret.
IASSC exams run through more than 8,000 testing centres across 165 countries plus 24/7 online proctoring, so scheduling rarely blocks a candidate.
One certification covers both Lean tools and Six Sigma statistics, from 5S, kanban and the seven wastes through to ANOVA, Mann-Whitney and CuSum charts.
The Green Belt recertification exam is only 50 questions in 90 minutes, a much smaller commitment than resitting the full 100 question exam every three years.
Exam Format & Structure
Duration
3 hours (180 minutes)
Questions
100
Passing Score
70 percent minimum
Question Types
- Multiple choice
- True or false
Delivery Method
Proctored at more than 8,000 testing centres in 165 countries, through PeopleCert Online Proctoring, or through IASSC Accredited Providers
- Closed book. Some exam forms include up to 10 additional non-graded questions beyond the 100.
- Approximately 20 questions come from each of the five sections of the IASSC Green Belt Body of Knowledge.
- A non-programmable four function or scientific calculator is permitted; graphing, programmable, phone and software calculators such as Minitab and SigmaXL are not.
- An IASSC reference document is made available as a download during the startup steps of the exam session.
- Online exam appointments can be booked 72 hours ahead at no extra fee, or sooner for a small additional fee.
How scoring works
Score scale
Percentage of graded questions correct
Score needed to pass
70 percent
Roughly what that means raw
70 of the 100 graded questions correct
When results arrive
IASSC does not publish a result turnaround time on its Green Belt certification page.
How the scale is built
IASSC scores the 100 graded multiple-choice and true or false questions and applies a single 70 percent threshold. Any additional non-graded questions on a form, up to 10 of them, do not count. There is no per-phase minimum and no compensatory weighting to work out, so 70 correct graded answers clears the exam regardless of which phases they came from.
- Successful candidates receive a PDF certificate with a certification number, a PNG badge, and an entry in the Official IASSC Certification Register.
- IASSC grants the right to use its certification marks and titles under the IASSC Marks Use Policy.
- The recertification exam uses the same 70 percent threshold across 50 questions.
- IASSC does not publish per-phase score reporting for the Green Belt exam.
Pacing and time budget
100 questions in 180 minutes gives you 108 seconds per question per question.
| At this point | You should have answered |
|---|---|
| 45 min | 25 |
| 90 min | 50 |
| 135 min | 75 |
| 170 min | 100 |
- Ten minutes held back at the end covers a review of flagged calculation items without cutting into the final block.
- True or false items usually take under 30 seconds, which banks time for the Analyze and Improve calculations.
- Hypothesis testing and regression items are the slowest on the paper, so expect the Analyze block to run over the 108 second average.
- Forms carrying up to 10 additional non-graded questions still allow the same three hours, so the effective per-question budget can drop to about 98 seconds.
- Locate the formulas you need in the IASSC reference document early rather than hunting for them mid-calculation.
Where the marks are
| Topic | Weight | Why it scores |
|---|---|---|
| Hypothesis testing with normal and non-normal data | Most of the 20% Analyze phase | Two of the five Analyze sub-sections are hypothesis testing, and sections 3.4 and 3.5 name the tests individually rather than as a category. Nothing else on the exam concentrates that many scored questions into one skill. |
| Measurement system analysis and process capability | Half of the 20% Measure phase | Gage R and R, bias, linearity, stability, and Cp against Cpk are heavily tested and easy to lose marks on because the distinctions are fine and the arithmetic is quick. |
| Statistical process control chart selection | Most of the 20% Control phase | Section 5.2 names eight charts: I-MR, Xbar-R, Xbar-S, U, P, NP, CuSum and EWMA. Selection questions are decision-table recall once the table is built. |
| Regression and residuals | Most of the 20% Improve phase | The Improve phase has only two sub-sections and both are regression, so almost every Improve question comes from correlation, regression equations, residuals, intervals or the Box-Cox transformation. |
| Six Sigma metrics: DPU, DPMO, FTY, RTY | Within the 20% Define phase | The Body of Knowledge asks candidates to derive these metrics, not just recognise them. They are fast marks with a calculator and they reappear in capability and control questions. |
| Process definition tools: SIPOC, FMEA, X-Y diagram | Within the 20% Measure phase | Recall-level questions that cost seconds rather than minutes, which makes them the best place to bank time for the Analyze block. |
| Lean enterprise: seven wastes, 5S, kanban, poka-yoke | Split across the Define and Control phases | Lean content appears in both the first and last phases of the Body of Knowledge, so it earns marks at two points on the paper for one block of study. |
| Project charter, cost of poor quality and benefits capture | Within the 20% Define phase | Scenario questions about scoping and financial justification are answerable from a well-drilled charter template and a clear grasp of internal, external, appraisal and prevention costs. |
The numbers
100 questions, 3 hours, closed book
Exam format
Source: IASSC Green Belt Certification page, iassc.org
70 percent
Minimum passing score
Source: IASSC Green Belt Certification page, iassc.org
$350 on the IASSC certification pages, $402 in the IASSC order store
Exam fee
Source: iassc.org certification pages and orders.iassc.org
None
Prerequisites
Source: IASSC Green Belt Certification page, iassc.org
3 years from the last day of the certification month
Current status window
Source: IASSC Recertification Policy, iassc.org
More than 8,000 centres in 165 countries
Test centre reach
Source: IASSC Green Belt Certification page, iassc.org
If you fail
Wait before retaking
IASSC does not publish a mandatory waiting period between attempts at the full Green Belt certification exam. Recertification exams are the exception and must be separated by at least two weeks.
Attempt limit
No published cap on attempts at the full certification exam. Recertification exams are limited to two attempts.
Retake fee
A new exam voucher is required for each attempt, listed at $350 on the IASSC certification pages and $402 in the IASSC order store.
PeopleCert sells a Take 2 re-sit option that must be bought no later than 15 minutes before the first sitting and cannot be bought after a failure. A Take 2 re-sit must be scheduled and taken within six months of the initial exam, and failing to show up for a Take 2 appointment without rescheduling beforehand forfeits the voucher. A failed recertification attempt applies Elapsed status rather than revoking the certification, and the holder can re-establish Current status by passing the full certification exam again.
Exam Domains & Topics
Frames the problem and the project. Candidates cover the meanings and history of Six Sigma, the Y equals f of x problem-solving strategy, voice of the customer, business and employee, Six Sigma roles, process definition, critical to quality characteristics, cost of poor quality, Pareto analysis, the core metrics DPU, DPMO, FTY and RTY, project charters, project metrics, financial benefit capture, and the Lean enterprise.
Key Topics to Master:
- Meanings and general history of Six Sigma and continuous improvement
- Deliverables of a Lean Six Sigma project
- The Y equals f of x problem solving strategy
- Voice of the customer, business and employee
- Six Sigma roles and responsibilities
- Critical to quality characteristics and cost of poor quality
- Pareto analysis and the 80:20 rule
- Deriving DPU, DPMO, FTY, RTY and cycle time
- Business case, project charter and financial benefits capture
- The seven elements of waste and 5S
Establishes what the process actually does today. Candidates work through cause and effect diagrams, process mapping with SIPOC and value stream maps, X-Y diagrams, failure modes and effects analysis, basic and descriptive statistics, normal distributions and normality testing, graphical analysis, measurement system analysis including precision, accuracy, bias, linearity, stability and gage R and R, and process capability for both variable and attribute data.
Key Topics to Master:
- Cause and effect fishbone diagrams
- Process mapping, SIPOC and value stream mapping
- X-Y diagrams and FMEA
- Basic and descriptive statistics
- Normal distributions and normality testing
- Graphical analysis techniques
- Precision and accuracy, bias, linearity and stability
- Gage repeatability and reproducibility
- Variable and attribute measurement system analysis
- Capability analysis, stability and monitoring techniques
The statistical heart of the exam and the phase most candidates fail on. Candidates cover multi-vari analysis, classes of distributions, inference, sampling techniques, the central limit theorem, the goals and risks of hypothesis testing including alpha and beta, practical against statistical significance, testing with normal data using t-tests, one sample variance and one way ANOVA, and testing with non-normal data across Mann-Whitney, Kruskal-Wallis, Mood's Median, Friedman, one sample sign, one sample Wilcoxon, proportion tests and chi-squared contingency tables.
Key Topics to Master:
- Multi-vari analysis and classes of distributions
- Sampling techniques and the central limit theorem
- Practical against statistical significance
- Alpha risk, beta risk and types of hypothesis test
- One and two sample t-tests and one sample variance
- One way ANOVA with tests of equal variance and normality
- Mann-Whitney, Kruskal-Wallis, Mood's Median and Friedman
- One sample sign and one sample Wilcoxon
- One and two sample proportion tests
- Chi-squared contingency tables and sample size calculation
Turns analysis into a modelled relationship between inputs and outputs. Candidates cover simple linear regression including correlation, regression equations and residuals analysis, then multiple regression analysis covering non-linear regression, multiple linear regression, confidence and prediction intervals, further residuals analysis, and data transformation using the Box-Cox method.
Key Topics to Master:
- Correlation and its limits as evidence of cause
- Regression equations and interpreting coefficients
- Residuals analysis in simple regression
- Non-linear regression
- Multiple linear regression
- Confidence intervals against prediction intervals
- Residuals analysis in multiple regression
- Data transformation and the Box-Cox transformation
Holds the gain after the project closes. Candidates cover Lean controls including control methods for 5S, kanban and poka-yoke mistake proofing, statistical process control from data collection through the eight chart types named in the Body of Knowledge, and Six Sigma control plans covering cost benefit analysis, the elements of a control plan and the elements of a response plan.
Key Topics to Master:
- Control methods for 5S
- Kanban pull signals
- Poka-yoke mistake proofing
- Data collection for statistical process control
- I-MR, Xbar-R and Xbar-S charts
- U, P and NP attribute charts
- CuSum and EWMA charts
- Choosing a control method for the data type
- Cost benefit analysis in control
- Elements of the control plan and the response plan
Recommended Study Plan
- 1Read the IASSC Green Belt Body of Knowledge top to bottom and mark every topic you cannot define
- 2Learn the Six Sigma roles: champion, process owner, Master Black Belt, Black Belt, Green Belt, Yellow Belt
- 3Write the Y equals f of x statement for a process you actually work on
- 4Separate voice of the customer, voice of the business and voice of the employee with one example each
- 5Practise converting defects, units and opportunities into DPU and DPMO by hand
- 1Draft a project charter with problem statement, goal statement, scope, team and timeline
- 2Calculate cost of poor quality for a scenario with rework, scrap and warranty costs
- 3Build a Pareto chart from a defect table and state what the 80:20 split tells you
- 4Memorise the seven elements of waste and the five S terms in order
- 5Compute first time yield and rolled throughput yield for a four-step process
- 1Draw a SIPOC for one process and extend it into a value stream map
- 2Build a fishbone diagram using the six M categories and convert the causes into an X-Y diagram
- 3Complete an FMEA table and calculate risk priority numbers from severity, occurrence and detection
- 4Practise reading a process map for non-value-added steps
- 5Answer 20 Define and Measure questions and record every miss
- 1Calculate mean, median, mode, range, variance and standard deviation by hand for a small data set
- 2Learn what a normality test reports and what a non-normal result forces you to change
- 3Read histograms, box plots, dot plots and run charts and say what each one hides
- 4Practise converting between standard deviation and sigma level
- 5Work through 15 descriptive statistics questions with a four function calculator only
- 1Separate precision from accuracy and bias from linearity from stability with a worked example each
- 2Interpret a gage R and R output and state the threshold at which a measurement system is unusable
- 3Run attribute agreement analysis on a pass or fail inspection scenario
- 4Calculate Cp, Cpk, Pp and Ppk and explain why Cpk can be lower than Cp
- 5Answer 25 Measure phase questions under time pressure
- 1Explain the central limit theorem in one sentence and why it lets you use normal-based tests
- 2Write null and alternative hypotheses for five different business questions
- 3Fix alpha and beta risk in your memory as producer risk and consumer risk with a worked case
- 4Practise sample size calculation for a mean and for a proportion
- 5Distinguish practical significance from statistical significance on a real p-value
- 1Run a one sample t-test and a two sample t-test and interpret both p-values
- 2Perform a one sample variance test and state when it applies
- 3Work a one way ANOVA including the test of equal variance that precedes it
- 4Build a decision tree that maps data type and question to the right normal-data test
- 5Answer 25 hypothesis testing questions and rewrite the misses as flashcards
- 1Match Mann-Whitney, Kruskal-Wallis, Mood's Median and Friedman to their data structures
- 2Work one sample sign and one sample Wilcoxon problems and note the difference between them
- 3Run one and two sample proportion tests on discrete pass or fail data
- 4Build and interpret a chi-squared contingency table
- 5Extend the week 7 decision tree to cover every non-parametric test named in the Body of Knowledge
- 1Calculate a correlation coefficient and state what it does not prove
- 2Fit a simple linear regression by hand on six data points and interpret the slope
- 3Plot residuals and identify the three patterns that invalidate a model
- 4Add a second predictor and explain what multiple regression buys you
- 5Separate a confidence interval from a prediction interval in a sentence a manager would follow
- 1Work a Box-Cox transformation and state the problem it solves
- 2Practise non-linear regression on a curved data set
- 3Write control methods that sustain each of the five S steps
- 4Design a kanban signal for a two-bin replenishment system
- 5List five poka-yoke devices from processes you have seen and classify each as prevention or detection
- 1Build a selection table for I-MR, Xbar-R, Xbar-S, U, P and NP charts by data type and subgroup size
- 2Learn what CuSum and EWMA detect that Shewhart charts miss
- 3Apply out-of-control rules to three charts and state the response for each signal
- 4Write a control plan with measurement, specification, frequency, method and reaction columns
- 5Draft a response plan for a single out-of-control signal
- 1Sit a 100 question practice test under a strict 180 minute timer
- 2Score by DMAIC phase and rank the five phases by weakness
- 3Consider the IASSC Green Belt Evaluation Exam, the non-proctored version IASSC sells to gauge readiness
- 4Spend two full sessions on the weakest phase only
- 5Redo every hypothesis testing question you missed in weeks 7 and 8
- 1Download the IASSC reference document and learn where each formula sits in it
- 2Practise every calculation with a non-programmable calculator, since Minitab is not permitted
- 3Time yourself on 20 calculation-heavy questions at 108 seconds each
- 4Rebuild the DPU, DPMO, FTY, RTY, Cp, Cpk, Z-score and sample size formulas from memory
- 5Re-read the Control phase chart selection table until it is automatic
- 1Sit a second full 100 question practice test and confirm you clear 80 percent
- 2Book the exam voucher and schedule the session, allowing 72 hours to avoid the rush fee
- 3Run the PeopleCert system check on the exact machine and network you will use
- 4Confirm your photo identification matches the name on the voucher
- 5Review only your flashcard misses on the final day rather than opening new material
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Best Study Resources
IASSC Green Belt Lean Six Sigma Body of Knowledge
Official syllabusThe definitive topic list the exam is built from, broken into Define, Measure, Analyze, Improve and Control with numbered sub-topics down to individual tests such as Mood's Median and the EWMA chart.
Free
IASSC Green Belt Certification page
Official exam specificationPublishes the 100 question count, three hour allowance, closed book rule, 70 percent minimum score, the absence of prerequisites, and the note that some forms carry up to 10 additional non-graded questions.
Free
IASSC Green Belt Evaluation Exam voucher
Non-proctored practice examIASSC sells an informal, non-proctored Green Belt evaluation exam intended to tell candidates whether they are ready to sit the official proctored certification exam.
$78 in the IASSC order store
IASSC reference document
Formula referenceThe reference sheet IASSC provides as a download during the startup steps of the exam session. Studying it in advance means you know which formulas you do not have to memorise and where each one sits.
Free
IASSC Accredited Provider directory
Training directoryIASSC lists the training organisations whose curricula have been assessed against the IASSC Body of Knowledge. Training is recommended but never required, and provider pricing is set independently.
Free to browse; provider course fees vary
NIST/SEMATECH e-Handbook of Statistical Methods
Reference textPublic-domain statistics handbook from the US National Institute of Standards and Technology covering hypothesis testing, process capability, gage studies and every control chart named in the Control phase.
Free
Minitab or SigmaXL trial
Statistical softwareUseful for building intuition on ANOVA, regression and control charts during study. Neither is permitted in the exam, so every calculation must eventually be rehearsed on a non-programmable calculator.
Free trial period, then paid licence
ASQ quality resources library
Free articles and templatesAmerican Society for Quality reference pages on SIPOC, fishbone diagrams, FMEA, control charts and process capability. Written against the ASQ body of knowledge but the tool mechanics match the IASSC syllabus.
Free
Lean Enterprise Institute learning resources
Articles and glossaryCovers the Lean half of the syllabus, including value stream mapping, the seven wastes, 5S, kanban and standard work, which the Define and Control phases both draw on.
Free
IASSC recertification policy
Policy referenceSets out the three year Current status window, the 90 day grace period after elapse, the two attempt limit two weeks apart, and the 50 question, 90 minute Green Belt recertification exam at 70 percent.
Free
Common Mistakes to Avoid
Studying Lean tools and skipping the statistics because the credential is called Lean Six Sigma.
The Analyze phase alone supplies about 20 questions and covers t-tests, ANOVA and seven non-parametric tests. Improve adds simple and multiple regression. Statistics carry about 40 of the 100 questions.
Practising every calculation inside Minitab or SigmaXL.
IASSC permits only a non-programmable four function or scientific calculator. Graphing calculators, programmable calculators, phone calculators and statistical software are barred. Rehearse the arithmetic the way you will do it on the day.
Memorising which test to run without learning why the data type forces the choice.
Build a decision tree with data type, number of samples and normality as the three branches. Exam items describe a situation and expect the test, so the tree is what gets scored, not the formula.
Confusing Cp with Cpk and Pp with Ppk.
Cp and Pp measure spread against the specification width and ignore centring. Cpk and Ppk penalise a process that is off centre. Cp uses within-subgroup variation, Pp uses overall variation. Work one example where Cp is 1.5 and Cpk is 0.8.
Assuming a low p-value settles a business question.
The Body of Knowledge names practical against statistical significance as a distinct topic. A statistically significant shift can be too small to fund, and exam scenarios test whether you can say so.
Treating all control charts as interchangeable.
Chart selection turns on data type and subgroup size. I-MR for individuals, Xbar-R for small subgroups, Xbar-S for larger subgroups, P and NP for defectives, U for defects per unit, CuSum and EWMA for small sustained shifts. The C chart is not in the IASSC Green Belt Body of Knowledge. Build a one-page selection table.
Booking the exam expecting to be told a scaled score and a domain breakdown.
IASSC publishes a single 70 percent minimum and does not publish a scaled score conversion or a result turnaround time on its certification pages. Plan around a flat percentage threshold, not a compensatory model.
Letting the certification lapse because IASSC says recognition is perpetual.
Recognition is perpetual but the status is not. Current status runs three years from the last day of the month of certification, then becomes Elapsed. The recertification exam must be taken no later than 90 days after that elapse date.
Buying a training course before checking whether the provider is IASSC accredited.
IASSC maintains a public directory of Accredited Providers whose curricula have been assessed against its Body of Knowledge. Training is optional, but a non-accredited course may be built against a different syllabus.
Reading the ASQ Green Belt handbook and assuming it maps one to one.
ASQ CSSGB is a separate credential with its own body of knowledge, a 110 question exam, a 483 USD fee and a three year work experience requirement. Tool mechanics overlap, but the topic list and the emphasis differ.
Exam Day Tips
- 1
Budget 108 seconds per question, which is 180 minutes divided by 100 questions, and check your position at every 25 question mark.
- 2
Download and open the IASSC reference document during the startup steps, because it is only available inside the exam session and not something you may bring.
- 3
Bring a non-programmable four function or scientific calculator and leave graphing and programmable models at home, since they will be refused.
- 4
Answer true or false items immediately and flag only genuine uncertainty, because those questions carry the same weight as calculation items.
- 5
Do the DPU, DPMO, FTY and RTY arithmetic on the calculator rather than in your head, since transposition errors cost whole questions.
- 6
For hypothesis testing items, identify the data type and sample count before reading the answer options, which stops the distractors from steering you.
- 7
For an online proctored session, clear the desk, close every application and run the PeopleCert system check on the same machine and network beforehand.
- 8
Have the photo identification you registered with ready, since PeopleCert verifies identity by photo ID before releasing the exam.
- 9
Schedule at least 72 hours ahead to avoid the additional fee IASSC charges for immediate sittings.
- 10
Never leave an item blank, because the threshold is a flat 70 percent of the graded questions and an unanswered item scores nothing.
Career Paths & Salary Ranges
Continuous improvement specialist
Runs DMAIC projects across a business unit, facilitates value stream mapping workshops and reports benefits to finance. BLS reports a May 2025 median annual wage of $101,860 for management analysts, with the 90th percentile at $171,640.
$102k-$172k
Industrial engineer
Designs process layouts, measurement systems and capacity models, and owns the technical side of measurement system analysis. BLS reports a May 2025 wage range for industrial engineers from $74,370 at the 10th percentile to $159,860 at the 90th.
$74k-$160k
Project management specialist
Coordinates improvement projects, tracks charters and controls schedule and scope for a portfolio of Green Belt work. BLS reports a May 2025 wage range for project management specialists from $61,580 at the 10th percentile to $167,970 at the 90th.
$62k-$168k
Industrial production manager
Owns plant output, quality and cost, and sponsors the Green Belt projects rather than running them. BLS reports a May 2025 median annual wage of $126,060 for industrial production managers, with the 90th percentile at $205,520.
$126k-$206k
Operations manager
Runs a service or logistics operation where control plans, kanban and statistical process control decide whether gains hold. BLS reports a May 2025 median annual wage of $105,770 for general and operations managers, with the 90th percentile at $253,390.
$106k-$253k
Prerequisites & Requirements
- None. IASSC sets no prerequisites for sitting the Certified Lean Six Sigma Green Belt exam.
- No training course is required, although IASSC recommends training through a qualified institution, trainer or corporate programme.
- No completed improvement project is required, unlike Green Belt programmes run by some employers.
- No prior Yellow Belt certification is required.
- IASSC recommends but does not require some real-world Lean Six Sigma work and project application experience.
- A photo identification document is required for identity verification by the proctor before the exam is released.
- Comfort with basic algebra and arithmetic on a non-programmable calculator, since statistical software is not permitted.
- The exam is offered in English, so working reading fluency in English is needed.
Frequently Asked Questions
How much does the IASSC Green Belt exam cost?
IASSC lists the Green Belt exam at 350 USD on its certification and on-demand testing pages, and the IASSC order store currently lists the Green Belt On-Demand Web-Based Certification Exam Voucher at 402 USD. Prices are quoted in US dollars worldwide. Training is a separate purchase from an accredited provider and IASSC does not set those fees.
What is the passing score?
70 percent. IASSC states that candidates must achieve a minimum score of 70 percent on the Certified Lean Six Sigma Green Belt Exam. There is no scaled score conversion published and no per-phase minimum, so the threshold is a flat percentage of the graded questions.
How many questions are on the exam?
100 multiple-choice and true or false questions, with approximately 20 from each of the five sections of the Body of Knowledge. Some forms of the exam include up to 10 additional non-graded questions on top of the 100.
What happens if I fail?
You buy another exam voucher and sit again. IASSC does not publish a mandatory waiting period between attempts at the full Green Belt certification exam, and it does not publish an attempt cap. PeopleCert sells a Take 2 re-sit option that must be purchased up to 15 minutes before the first sitting, cannot be bought after a failure, and must be used within six months of the initial exam.
Are there any prerequisites?
No. IASSC requires no training, no work experience, no completed project and no prior Yellow Belt to sit the Green Belt exam. Training and real-world project experience are both recommended and neither is required.
How does this compare with the ASQ Certified Six Sigma Green Belt?
They are separate credentials from separate bodies. The ASQ CSSGB is a 110 question exam with 4 hours and 18 minutes of exam time, costs 483 USD with 283 USD retakes, and requires three years of full-time paid work experience in one or more areas of the ASQ body of knowledge. The IASSC ICGB is 100 questions in three hours with no experience requirement at all.
How long is the certification valid?
IASSC recognises certifications perpetually and indefinitely, but applies a status classification on top. A certification carries Current status for three years from the last day of the month in which it was achieved, then moves to Elapsed unless the holder recertifies. Elapsed certifications are not revoked and remain in the IASSC register.
What does recertification involve?
A 50 question, closed book, proctored exam with a 1.5 hour allowance and the same 70 percent threshold, drawing approximately 10 questions from each major section. IASSC lists the fee at 175 USD on the recertification page and at 268 USD in its order store. Recertification exams are limited to two attempts separated by at least two weeks, and must be taken no later than 90 days after the elapse date.
Can I take the exam online?
Yes. IASSC runs on-demand web-based certification testing through PeopleCert Online Proctoring, available 24 hours a day, 365 days a year. Booking 72 hours ahead carries no additional fee, and IASSC charges a small additional fee to sit immediately.
What am I allowed to bring into the exam?
A non-programmable standard four function calculator or a non-programmable scientific calculator. Graphing calculators, programmable calculators, calculators on mobile phones and software calculators such as Minitab and SigmaXL are all barred. The exam is closed book and you may not bring the IASSC reference document, which is supplied as a download during the exam startup steps.
How is identity verified?
PeopleCert collects photo identification and records the session. For online proctored exams the proctor connects by webcam, verifies the candidate against photo ID, and monitors video, sound and the desktop for the full session. Have the same photo ID you registered with to hand, because the proctor will not release the exam without it.
Where can I sit the exam in person?
IASSC states its exams are administered in more than 8,000 testing centres located within 165 countries, and also through hundreds of IASSC Accredited Providers who are authorised to facilitate IASSC exams as part of their training programmes.
When do I get my result?
IASSC does not publish a result turnaround time on its Green Belt certification page. Successful candidates receive a PDF certificate carrying a certification number, a PNG badge, an entry in the Official IASSC Certification Register, and the right to use the IASSC certification marks and titles under the IASSC Marks Use Policy.
Does IASSC publish a pass rate?
No. IASSC does not publish pass rates or score distributions for any of its Lean Six Sigma exams. The closest readiness signal from IASSC itself is the non-proctored Green Belt Evaluation Exam, which the order store lists at 78 USD.
Are accommodations available?
IASSC does not publish an accommodations policy on its Green Belt certification page. Because exams are delivered through PeopleCert and through IASSC Accredited Providers, accommodation requests are handled by the delivery organisation and need to be raised with them before booking rather than on the day.
What is the hardest part of the exam?
The Analyze phase, which supplies about 20 questions covering one and two sample t-tests, one sample variance, one way ANOVA, Mann-Whitney, Kruskal-Wallis, Mood's Median, Friedman, one sample sign, one sample Wilcoxon, proportion tests and chi-squared contingency tables. Candidates without a statistics background usually need three to four weeks on this phase alone.
Is the exam offered in languages other than English?
IASSC publishes its Green Belt exam specification in English and does not list alternative exam languages on its certification page. Accredited Providers deliver training in many languages, but the certification exam itself is the IASSC exam.
Should I do Yellow Belt first?
Not necessarily. The IASSC Certified Yellow Belt is a 60 question, two hour exam covering the foundational elements and targeting a cognitive level up to Analyze, while the Green Belt targets up to Evaluate. Since Green Belt has no prerequisites, candidates with process improvement exposure usually go straight to Green Belt and treat Yellow Belt as a team-member credential.
How long does it take to prepare?
Plan 90 to 120 hours over 12 to 14 weeks if you have no formal statistics background. Candidates who already run hypothesis tests and control charts at work typically need 40 to 60 hours, mostly on the Lean content and on the specific non-parametric tests named in the Body of Knowledge.
Can I cancel or refund an exam voucher?
PeopleCert terms allow cancellation within 14 days of the initial payment. If you have already booked a specific exam date, cancellation within those 14 days is allowed only when the booked date is at least 14 days after the request. Vouchers bought from an Accredited Training Organization are refunded by that organisation, not by PeopleCert.
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