Lean Six Sigma Green Belt Study Guide (2026) - Pass on Your First Attempt
📋 2026 Edition  ·  Updated May 2026

Lean Six Sigma Green Belt
six-sigma-green-belt Study Guide — Pass First Attempt

Complete exam coverage for the Lean Six Sigma Green Belt. Every domain, every key topic — structured so you study smart, not hard. Built around the official exam blueprint.

100 (ASQ) / 150 (IASSC)
Questions
270 min
Duration
580/800 (ASQ) / 385/500 (IASSC)
Passing score
5
Domains
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92%
First-attempt pass rate
47K+
Candidates prepared
4.9★
Average rating
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Define Phase
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Measure Phase
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Analyse Phase
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Improve Phase
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Control Phase
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Exam at a Glance

Everything you need to know before you start

Key facts about the Lean Six Sigma Green Belt exam structure, format, and scoring.

🆔
six-sigma-green-belt
Exam code
📝
100 (ASQ) / 150 (IASSC) questions
Total questions
⏱
270 minutes
Duration
🎯
580/800 (ASQ) / 385/500 (IASSC)
Passing score
📋
5 domains
Exam domains
📅
Valid 3 years
Certification validity
🌐
Online / In-person
Testing mode
🏆
Globally recognised
Credential type
ℹ️
Scoring method: . The exam may include unscored pilot questions — treat every question seriously.
Focus Areas

What should you study for the Lean Six Sigma Green Belt exam?

To pass the Lean Six Sigma Green Belt certification exam, you should focus on these core domains. The exam tests your ability to apply concepts in real-world scenarios — not just memorise definitions.

⚠️
Common mistake: Candidates memorise terminology but struggle with scenario-based questions. Focus on when to use what, not just what exists.
🔐
Define Phase (16%)
Covers project selection, problem framing, Voice of the Customer, and project charter development.
🏗
Measure Phase (20%)
Covers data collection, measurement system analysis, process capability, and establishing a baseline.
⚡
Analyse Phase (24%)
Covers root cause analysis, statistical hypothesis testing, regression, and identifying key process inputs (Xs).
💰
Improve Phase (24%)
Covers generating solutions, Design of Experiments (DOE), Lean flow improvement, and pilot testing.
🔄
Control Phase (16%)
Covers Statistical Process Control (SPC), control charts, response plans, and sustaining improvement.
Full Syllabus

Lean Six Sigma Green Belt Exam Syllabus and Topics

The Lean Six Sigma Green Belt exam is divided into 5 domains. Each domain tests specific skills and contributes to your overall score. Click any domain to expand topics.

Define Phase
Covers project selection, problem framing, Voice of the Customer, and project charter development.
16% ▼
Problem Definition and Business Case
Project charter components: problem statement, goal statement, scope, team, timeline, business case
SMART project goals: Specific, Measurable, Achievable, Relevant, Time-bound
Linking Six Sigma projects to strategic goals
Project selection criteria: financial impact, feasibility, and strategic alignment
DMAIC vs DMADV (Design for Six Sigma): when to use each
Voice of the Customer
VOC collection methods: surveys, interviews, focus groups, complaint analysis
Kano model: basic, performance, and excitement needs
CTQ (Critical to Quality) tree: translating customer needs to measurable requirements
QFD (Quality Function Deployment) and House of Quality
SIPOC diagram: Suppliers, Inputs, Process, Outputs, Customers
Lean Fundamentals
Five Lean principles: value, value stream, flow, pull, perfection
Eight wastes (TIMWOODS): Transport, Inventory, Motion, Waiting, Over-processing, Overproduction, Defects, Skills
Value-added vs non-value-added activities
Value stream mapping (VSM): current state and future state maps
Process cycle efficiency: value-added time / total lead time
~16 questions
128 marks
16% of exam weight
Measure Phase
Covers data collection, measurement system analysis, process capability, and establishing a baseline.
20% ▼
Data Types and Collection
Variable (continuous) vs attribute (discrete) data
Data collection plan: who collects, how, when, and where
Sampling methods: random, stratified, systematic
Check sheets, Pareto charts, and histograms for initial data summary
Operational definitions: defining what you are measuring precisely
Measurement System Analysis (MSA)
Gauge R&R (Repeatability and Reproducibility): assessing measurement variation
Bias, stability, linearity, and resolution in measurement systems
%R&R < 10%: acceptable; 10–30%: may be acceptable; >30%: unacceptable
Attribute MSA: Kappa statistic for categorical agreement
Sources of measurement error and how to reduce them
Capability Metrics
Process capability indices: Cp, Cpk, Pp, Ppk
Cp: potential capability (centred process); Cpk: actual capability (includes mean shift)
Six Sigma targets: Cpk ≥ 1.33 (4σ), Cpk ≥ 1.67 (5σ)
DPMO (Defects Per Million Opportunities) and sigma level conversion
Rolled Throughput Yield (RTY) and First Pass Yield (FPY)
Baseline sigma calculation from defect rate
~20 questions
160 marks
20% of exam weight
Analyse Phase
Covers root cause analysis, statistical hypothesis testing, regression, and identifying key process inputs (Xs).
24% ▼
Root Cause Tools
Cause-and-effect (fishbone / Ishikawa) diagram: 6M categories
5 Whys technique: iterative questioning to root cause
Fault tree analysis (FTA): top-down failure analysis
Failure Mode and Effects Analysis (FMEA): RPN = Severity × Occurrence × Detection
Affinity diagrams and interrelationship digraphs
Hypothesis Testing
Null hypothesis (H₀) vs alternative hypothesis (H₁)
Type I error (α, false positive) and Type II error (β, false negative)
p-value interpretation: p < α → reject H₀
t-tests: one-sample, two-sample (independent), and paired t-test
ANOVA: comparing means across more than two groups
Chi-square test: testing independence of categorical variables
Correlation and Regression
Pearson correlation coefficient (r): strength and direction of linear relationship
Simple linear regression: equation, R², and residual analysis
Multiple regression: interpreting coefficients and interaction terms
Scatter plots and identifying outliers and influential points
Regression assumptions: linearity, normality of residuals, homoscedasticity
Non-Parametric and Other Tests
When to use non-parametric tests: non-normal data, small samples
Mann-Whitney U test: non-parametric alternative to two-sample t-test
Kruskal-Wallis test: non-parametric alternative to one-way ANOVA
Box plots and normal probability plots for distribution assessment
~24 questions
192 marks
24% of exam weight
Improve Phase
Covers generating solutions, Design of Experiments (DOE), Lean flow improvement, and pilot testing.
24% ▼
Idea Generation and Prioritisation
Brainstorming and brainwriting for solution generation
Solution selection matrix: weighting criteria and scoring
Pugh concept selection matrix
Poka-yoke (mistake proofing): prevention vs detection controls
Kaizen events: rapid improvement workshops
DOE Fundamentals
Full factorial designs: 2k designs, main effects, and interaction effects
Fractional factorial designs: resolution and confounding
Response Surface Methodology (RSM): optimising factor levels
Taguchi methods: robust design and noise factors
Interpreting main effects plots, interaction plots, and Pareto of effects
Flow and Pull Implementation
Single-piece flow vs batch processing
Kanban systems: pull signals, card types, and WIP limits
5S methodology: Sort, Set in order, Shine, Standardise, Sustain
Total Productive Maintenance (TPM) and OEE (Overall Equipment Effectiveness)
Cycle time, takt time, and bottleneck identification
~24 questions
192 marks
24% of exam weight
Control Phase
Covers Statistical Process Control (SPC), control charts, response plans, and sustaining improvement.
16% ▼
Control Charts
Control chart types: X-bar and R, X-bar and S, I-MR, p, np, c, u charts
Variable vs attribute charts: when to use each
Control limits vs specification limits: critical distinction
Western Electric rules for detecting special cause variation
Common cause vs special cause variation: responding appropriately
Out-of-control signals: points beyond control limits, runs, trends
Control Documentation
Control plan: process name, input/output, specification, measurement, sample size, frequency, reaction plan
Standard operating procedures (SOPs) and work instructions
FMEA update post-improvement: revised RPN scores
Visual management: dashboards, displays, and standard work
Knowledge transfer and training plan for sustainment
~16 questions
128 marks
16% of exam weight
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Study Plan

Lean Six Sigma Green Belt Structured Study Roadmap

Designed for candidates studying 1-2 hours per day. Select your timeline below.

Exam Strategy

Tips to pass Lean Six Sigma Green Belt on your first attempt

Tactical advice beyond content knowledge — what separates candidates who pass from those who retake.

🗓
FMEA RPN calculation (Severity × Occurrence × Detection) is tested in multiple questions — know how to calculate it and how to prioritise which failure modes to address first.
🔍
Understand Cp vs Cpk deeply: Cp measures potential (assumes centred process); Cpk measures actual performance. A process can have a good Cp but poor Cpk if the mean is off-centre.
⏭
Control chart selection is a common question type: use X-bar and R for variable data with subgroups; use I-MR for individual measurements; use p-chart for proportion defective (variable n); use c-chart for count of defects in fixed area.
📊
Know the difference between common cause variation (random, always present) and special cause variation (assignable, requires investigation) — the correct response to each is tested repeatedly.
🔁
Hypothesis testing: if p < α (typically 0.05), reject the null hypothesis. Practise interpreting p-values in context — many questions present a p-value and ask what it means.
🧪
The SIPOC diagram is Define phase, not Measure — know which tools belong to which DMAIC phase, as misattribution is a common distractor.
📝
DOE questions often ask you to identify the correct experiment type: full factorial tests all combinations; fractional factorial is more efficient but introduces confounding.
🎯
For the ASQ open-book exam, prepare tabs in the ASQ Green Belt Primer for key formulas (capability indices, control chart constants, sigma conversion tables) — you cannot afford to look everything up from scratch.
🗓
Takt time = Available production time / Customer demand rate — know this formula and be able to apply it in a process improvement scenario.
🔍
Value stream mapping questions test your ability to identify waste and calculate process cycle efficiency (PCE = VA time / total lead time) — both are standard Lean topics.
Recommended Resources

Official and trusted study materials

Curated resources ranked by usefulness. Quality over quantity — focus on a small set of authoritative sources.

Official
Official Exam Guide
The authoritative blueprint. Know every objective before studying anything else.
→ Vendor website
Practice Tests
Edureify Practice Tests
Full-length Lean Six Sigma Green Belt simulations with detailed per-domain analysis and explanations.
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Video Course
Structured Video Course
Pick one highly-rated course and complete it end-to-end before switching resources.
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Reference
Domain Cheat Sheets
One-page summaries for each Lean Six Sigma Green Belt domain — ideal for last-week revision.
→ Get free Cheat Sheet
Community
Study Groups & Forums
Reddit r/certifications and exam-specific Discord servers for peer support and tips.
→ Reddit / Discord
AI Tutor
Edureify AI Mentor
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⚠️
Avoid brain dumps. Sites selling "real exam questions" violate most vendor NDAs and are legally risky. Questions rotate regularly — brain dumps lead to overconfidence on outdated material and a higher retake rate.
Reviews

What candidates say after passing

★★★★★
"Passed Lean Six Sigma Green Belt on my first attempt after 5 weeks. The domain-level diagnostic showed me exactly where my gaps were — I stopped wasting time on topics I already knew."
Rahul S.
Solutions Architect, Bangalore
★★★★★
"The structured study plan kept me on track. I tried studying on my own for 3 months and failed. With Edureify's roadmap I passed in 6 weeks."
Priya M.
Cloud Engineer, Mumbai
★★★★★
"The AI mentor was like having a personal tutor available at 2am. Every concept I didn't understand was explained until I got it. Invaluable for the Define Phase domain."
David K.
DevOps Engineer, London
FAQ

Frequently asked questions about Lean Six Sigma Green Belt

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