Which body should I certify with - IASSC or ASQ?

Both are well known. IASSC is vendor-neutral and exam-only with no prerequisites; ASQ's Green Belt is widely respected and has experience requirements. Check which your employer or industry prefers, since there is no single global authority for Six Sigma.

Do I need training before the IASSC Green Belt exam?

No. There are no prerequisites to sit the IASSC exam. Training and real project experience are recommended but not required, so you can self-study against the published body of knowledge.

What is the difference between Green Belt and Black Belt?

A Green Belt supports or leads smaller improvement projects, often part-time under a Black Belt. A Black Belt leads larger projects full-time and goes deeper into statistics and the Control phase. Green Belt is the common starting professional level.

DMAIC is the core Six Sigma improvement method: Define the problem, Measure the current process, Analyze the root causes, Improve the process, and Control the result. The exam is organised around these phases.

Does the certification expire?

Historically IASSC certifications did not expire. IASSC now administers its exams with PeopleCert and recertification options exist, so confirm the current validity rules with IASSC before you rely on it.

Project Management

Lean Six Sigma Green Belt (IASSC ICGB)

intermediate

IASSC Certified Lean Six Sigma Green Belt

By The Exam Atlas Editorial Team · Verified 2026-06-05

Free ICGB practice questions 90 questions with full answer explanations. No sign-up. Start practice →

Overview

The IASSC Certified Lean Six Sigma Green Belt (ICGB) validates that you understand Lean Six Sigma process improvement and can support or lead smaller improvement projects. IASSC is a vendor-neutral certification body, and its exam tests a published body of knowledge organised around the DMAIC method: Define, Measure, Analyze, Improve and Control.

A Green Belt typically works on improvement projects part-time, often under a Black Belt, applying data and statistics to reduce defects and variation. The IASSC exam is exam-only with no prerequisites, so it suits people who want a recognised, independent credential. Note that several bodies certify Six Sigma (IASSC, ASQ and others); this page covers the IASSC route specifically.

✓ Who it is for

Professionals working on process and quality improvement, often part-time
Operations, manufacturing and supply-chain staff who reduce defects and variation
Project and continuous-improvement team members applying data to problems
People supporting larger Six Sigma projects under a Black Belt
Anyone wanting a recognised, no-prerequisite entry into Lean Six Sigma

✕ Who it is not for

Those wanting to lead large improvement programmes - the Black Belt goes deeper.
People needing a specific employer's or ASQ's credential - check which body they require.
Anyone expecting a project-management credential - this is process improvement, not PM.

Exam structure

Define	Roughly a fifth of the exam (about 20 of 100 questions, like every section). Covers the basics and fundamentals of Six Sigma, selecting Lean Six Sigma projects, and the Lean enterprise.
Measure	Process definition, Six Sigma statistics, measurement system analysis (MSA), and process capability.
Analyze	Patterns of variation, inferential statistics, and hypothesis testing with both normal and non-normal data.
Improve	Simple linear regression and multiple regression analysis. (Unlike the Black Belt, the Green Belt does not cover design of experiments.)
Control	Lean controls, statistical process control (SPC), and Six Sigma control plans to sustain improvements.

Realistic study time

With some process / data background ~6-10 weeks part-time
New to Six Sigma and statistics Longer; budget time for the Measure and Analyze statistics

Bars show relative effort, not a guarantee. Your time depends on background and study method.

Turn this into a week-by-week schedule with the Study Plan Generator.

What it really costs

Exam voucher ~US$350 confirm current pricing with IASSC

Training Optional; many free and paid Lean Six Sigma Green Belt courses exist

Fees change and vary by region. Confirm the current amount on the official site before you register.

Want your full out-of-pocket figure? Try the Cost Calculator.

Salary & career value

Indicative ranges for orientation only - not surveyed data, and not financial or career advice. Sources and date below.

These are indicative US ranges for the process- and quality-improvement roles a Green Belt supports, not for the exam alone; a Green Belt typically works part-time on smaller projects, so pay sits below a full-time Black Belt scope. Figures vary widely by region, industry and experience, and the certification is one factor among many. Aggregators such as Payscale and Glassdoor put Green Belt holders roughly in the US$80k-120k band depending on role.

Pass rate: Not published. IASSC does not release an official pass rate for the Lean Six Sigma Green Belt exam. The required score is a minimum of 70%, but no official percentage of candidates who pass is published - treat any figure you see online as an unofficial estimate.

Process / Quality Analyst $60,000 - $85,000

Lean Six Sigma Green Belt $80,000 - $110,000

Continuous Improvement Specialist $90,000 - $120,000

Quality / Process Engineer $95,000 - $130,000

Indicative annual pay (USD), each role's typical band on a shared scale.

Other markets (indicative)

United Kingdom	~£40k-60k
Canada	~CA$70k-100k
Australia	~A$80k-115k

Jobs that often ask for it:

Process Improvement Analyst
Continuous Improvement Specialist
Quality Analyst
Quality Engineer
Operations Analyst

Is it worth it?

Worth it for people in operations, quality and process-improvement roles, where Lean Six Sigma is widely recognised and a Green Belt signals practical capability. Check which certifying body your employer or industry prefers (IASSC, ASQ and others differ), and consider the Black Belt if you will lead larger projects.

Not sure this is the right exam for you? Compare your options with the Exam Finder.

Our specialty · side by side

Compare ICGB with other exams

Independent, like-for-like comparisons to help you choose the right one.

VS Lean Six Sigma Black Belt vs Green Belt: which should you take? Compare →

What to do next

From Green Belt, the IASSC Black Belt goes deeper into statistics and leading larger improvement projects. Lean Six Sigma also pairs well with project-management credentials like the PMP.

On exam day

100 closed-book questions in three hours, proctored, with a 70% pass mark; some forms add up to 10 unscored questions. Confirm the current format on the IASSC certification page beforehand.

Keeping your certification

Confirm current validity and any recertification requirements with IASSC, since administration moved to PeopleCert.

FAQ

Which body should I certify with - IASSC or ASQ?: Both are well known. IASSC is vendor-neutral and exam-only with no prerequisites; ASQ's Green Belt is widely respected and has experience requirements. Check which your employer or industry prefers, since there is no single global authority for Six Sigma.
Do I need training before the IASSC Green Belt exam?: No. There are no prerequisites to sit the IASSC exam. Training and real project experience are recommended but not required, so you can self-study against the published body of knowledge.
What is the difference between Green Belt and Black Belt?: A Green Belt supports or leads smaller improvement projects, often part-time under a Black Belt. A Black Belt leads larger projects full-time and goes deeper into statistics and the Control phase. Green Belt is the common starting professional level.
What is DMAIC?: DMAIC is the core Six Sigma improvement method: Define the problem, Measure the current process, Analyze the root causes, Improve the process, and Control the result. The exam is organised around these phases.
Does the certification expire?: Historically IASSC certifications did not expire. IASSC now administers its exams with PeopleCert and recertification options exist, so confirm the current validity rules with IASSC before you rely on it.

Related exams

PMP - Project Management Professional (PMI) - Project Management Institute (PMI)
CAPM (PMI) - Project Management Institute (PMI)
ITIL 4 Foundation (PeopleCert) - PeopleCert (AXELOS)