Lean Six Sigma Yellow Belt Certification Requirements

Updated on 29 September 2026. What’s new: iassc keeps a yellow belt current for three years, then a 30-question recertification exam is needed to renew it

Your manager has asked you to join a Lean Six Sigma project, and the Green Belt running it suggests you get a Yellow Belt first. The ICYB is that exam: the IASSC Certified Lean Six Sigma Yellow Belt, 60 multiple-choice and true/false questions in 120 minutes, a 70% pass mark and a USD $250 fee, with no prerequisites. It tests the Define, Measure and Control topics at foundation level. This guide covers what each topic asks, a worked example, a four-week study plan and how the certificate stays current.

What does ICYB mean, and what does the exam involve?

ICYB is the short name for the IASSC Certified Lean Six Sigma Yellow Belt, the entry-level credential from the International Association for Six Sigma Certification. IASSC describes the holder as someone who knows the foundations of Lean Six Sigma, can lead a limited improvement project, or can act as a team member on a larger project run by a Green Belt or Black Belt, usually in a part-time role.

The person who passes is not expected to design experiments or run regression models. They are expected to recognise waste, describe a process clearly, read basic statistics and graphs, judge whether a measurement can be trusted, and keep an improvement in place once the team has made it. That practical, supportive level shapes every question on the paper.

The figures below are the ones to plan around.

ICYB or the IASSC Certified Lean Six Sigma Yellow Belt certification is a testament to proficiency in fundamental Lean Six Sigma principles and methodologies. Whether you aim to advance your career or deepen your understanding of process improvement strategies, effective preparation is essential to obtain this certification. Here are some study tips to help you prepare thoroughly for the ICYB certification exam.

Who Is An ICYB?

ICYB, or the IASSC Certified Lean Six Sigma Yellow Belt, is a professional who has a strong grasp of the fundamental principles of the Lean Six Sigma Methodology. They can lead minor improvement projects or contribute as a team member in more complex improvement initiatives led by a Certified Green Belt or Certified Black Belt, usually in a part-time capacity. A Lean Six Sigma Yellow Belt possesses a comprehensive understanding of the basic elements of the Lean Six Sigma Method, including proficiency in the areas covered within the Define, Measure, and Control (DMC) phases outlined in the IASSC Lean Six Sigma Yellow Belt Body of Knowledge. They are adept at implementing, executing, interpreting, and applying Lean Six Sigma techniques, albeit within a limited or supportive framework.

A Kanban system is effective when three things hold together: work starts only because downstream demand asks for it, every stage has a hard cap on how much can sit in it, and the team watches how long items take to get through. With those in place, inventory and queues shrink and delivery becomes predictable. Without the caps, Kanban turns into a colourful status display that changes nothing.

That is the short answer, and it holds for a car plant and for a software team alike. The longer answer explains why the caps matter so much, how to size them, which numbers prove the system is working, and where Kanban is the wrong tool. This page covers the method from its origin in Toyota's machine shop to the boards used by service desks today, and closes with where Kanban appears in the IASSC Lean Six Sigma bodies of knowledge, because it is one of the Lean controls those exams expect you to understand.

What is a Kanban system, and where did the cards come from?

The Japanese word kanban means signboard. In production, a kanban is a signal that authorises work: make this part, or move this container, in this quantity. The signal was originally a card that travelled with a box of parts, and Wikipedia's account of the kanban scheduling system credits Taiichi Ohno, an industrial engineer at Toyota, with developing it to improve manufacturing efficiency. It is also known in the automotive industry as the Toyota nameplate system.