IASSC Lean Six Sigma Green Belt Book

Updated on 29 September 2026. What’s new: iassc lists the green belt exam at usd $350 and needs no work experience to sit it or to hold the certificate

The ICGB is the IASSC Certified Lean Six Sigma Green Belt exam: 100 closed-book questions in 180 minutes, a 70% pass mark and a USD $350 fee, with no prerequisites to sit it. About 20 questions come from each of five sections, Define, Measure, Analyze, Improve and Control, so no phase can be skipped. This guide sets out the paper, the topics inside every section, how to choose the right hypothesis test and a six-week study plan.

People searching for the ICGB meaning are usually asking two things at once. The letters stand for the IASSC Certified Lean Six Sigma Green Belt, and IASSC is the International Association for Six Sigma Certification, an independent body that certifies knowledge rather than training. It does not run courses. It sets a Body of Knowledge, writes the exam and issues the certificate, which is why the same exam can be reached after a classroom course, a company programme or plain self-study.

Six Sigma is a top quality management method that seeks to attenuate or eradicate defects or errors in products and enterprise companies. Initially developed to enhance manufacturing processes, the instruments and methods utilized in Six Sigma are thought of industry-agnostic, which suggests they've been efficiently utilized in such sectors as aeronautics, electronics, prescription drugs, retail and more.

The "sigma" a part of Six Sigma refers to the knowledge evaluation portion of the method. Following Six Sigma strategies, a crew gathers, and analyzes information about product manufacture or service creation/supply to find out the usual deviation (sigma) of the mean and the closest customer specification limit. The aim is to restrict defects or errors to a maximum of 3.4 per million opportunities.

Organizations which have adopted Six Sigma processes may see improved customer support, shorter cycle times and higher compliance with laws and enterprise growth standardization. Nevertheless, the trials of Six Sigma make its operations considerably tough to implement, and it usually takes months or years earlier than all related staff is on board, following the procedures carefully and persistently sufficient to comprehend such advantages and worth.

A Six Sigma belt is a bill before it is a promotion: sitting the Yellow, Green and Black exams in turn costs $1,050 in IASSC vouchers, or $1,502 at ASQ's non-member rates, before any training or project time. So the useful question is not which colour sounds best but which rung your job will actually use. Yellow supports a project, Green runs one part-time, Black leads them full-time, and Master Black coaches the people who do.

How many Six Sigma belts are there, and what does each one do on a project?

The ladder borrows its colours from martial arts, and the working version has four rungs that vendors certify: Yellow, Green, Black and Master Black. Two more colours turn up in job adverts and training catalogues. White usually means an awareness course of a few hours with no exam behind it, and Brown is a label some training providers place between Green and Black. ASQ's and IASSC's exam lists start at Yellow and build no exam around White or Brown, so treat those two as course names, not credentials.

What separates the real rungs is not how much statistics you can recite. It is how much of a project you are trusted with, and how much of your working week it takes.