EXIN LSSA Lean Six Sigma Yellow Belt key terms

A process-improvement philosophy that focuses on finding and removing waste so that work flows steadily and value reaches the customer with the shortest possible delay and effort.

A data-driven improvement approach that reduces variation and defects in processes, aiming for extremely low defect rates and consistent, predictable output that meets customer requirements.

The five-phase improvement cycle used for existing processes: Define, Measure, Analyze, Improve and Control. Each phase has defined deliverables and a review gate before the next phase starts.

A step that the customer would willingly pay for because it changes the product or service toward what they want, and that is done right the first time.

Any activity that consumes time, effort or resources without adding value for the customer. Lean typically groups waste into categories such as transport, inventory, motion, waiting, overproduction, overprocessing and defects.

A step that does not increase value for the customer. It may be pure waste to remove, or necessary waste such as regulatory checks that currently cannot be avoided.

A visual diagram of the steps, information flows and delays that a product or service passes through, used to spot where value is added and where waste and waiting occur.

A picture of the sequence of steps in a process, showing who does what and where decisions are made, so the team shares one accurate view of how work really flows.

A high-level view of a process that lists its Suppliers, Inputs, Process steps, Outputs and Customers. It scopes the project and shows which inputs and outputs matter most.

The collected needs, expectations and complaints of customers, gathered through interviews, surveys, complaints or observation, and translated into measurable requirements the process must satisfy.

A measurable characteristic that expresses what the customer requires, turning a vague wish into a specific target with a metric and limits that the process can be judged against.

A short, factual description of the gap between current and desired performance, stating what, where, when and how big the gap is, without guessing at causes or solutions.

The measurable target a project intends to reach, including the metric, the baseline, the target level and a deadline, so success can be judged objectively at project closure.

A short document that authorizes an improvement project. It records the problem, goal, scope, business case, team members, milestones and sponsor, and protects the team from shifting expectations.

The boundary that states which processes, locations, products or time periods a project will cover and which it explicitly will not, preventing the effort from spreading too thinly.

Any person or group affected by or able to influence the process or the project, such as customers, staff, managers or suppliers. Their interests shape how changes are received.

The senior manager who owns the project's business case, provides resources and authority, removes organizational obstacles and approves the charter and results.

A team member with basic knowledge of Lean and Six Sigma who contributes data, participates in analysis and improvement work, and supports the project lead without running complex statistics alone.

A trained practitioner who leads smaller improvement projects part-time, applies the DMAIC tools and often coaches Yellow Belts on data collection and improvement work.

A full-time improvement expert who leads complex cross-functional projects, applies advanced statistical methods and mentors Green and Yellow Belts.

A written agreement on which data will be gathered, how, by whom, where and when, including clear operational definitions, so that measurements are consistent and trustworthy.

A precise description of how a characteristic is measured or counted, including what is included, excluded and how decisions are made, so different people measure the same thing the same way.

A study that checks whether the measuring method itself is reliable, separating real process variation from variation caused by the gauge, the appraiser or the procedure.

Measurements that can take any value on a scale, such as time, weight or length. They carry more information and allow stronger analysis than counts or categories.

Values that fall into separate categories or whole counts, such as pass or fail, defect type or number of complaints. Useful for proportions but less informative than continuous measurements.

The natural differences between repeated results of the same process. Understanding its size and sources is central to Six Sigma because excess variation creates defects and unpredictability.

Ordinary, everyday variation built into how a process is designed and run. It affects all output and can only be reduced by changing the process itself.

Unusual variation that comes from a specific, identifiable event or change rather than normal process behavior, often shown as an outlier or pattern on a control chart.

Any output or step that fails to meet a customer requirement or internal specification, forcing rework, scrap, complaint handling or other corrective effort.

The boundary set by the customer or design that defines acceptable performance. Results outside these limits are treated as defects, regardless of how the process normally behaves.

The underlying reason a problem occurs, which, if removed, prevents the problem from recurring. It differs from a symptom, which only shows that something is wrong.

A simple technique that repeatedly asks why a problem happens, moving from symptom toward underlying cause. Usually three to five rounds are enough to reach an actionable cause.

A cause-and-effect diagram shaped like a fish skeleton, with the problem at the head and candidate causes grouped on branches, used to organize brainstorming before data confirms which causes matter.

A bar chart that orders causes or defect types from most to least frequent, making it easy to see which few issues account for most of the problem so effort is focused there.

A change made to remove or reduce a confirmed root cause. It is chosen and tested against evidence rather than adopted simply because it is familiar or easy.

A small, controlled trial of a proposed change before full rollout, used to check whether it actually improves results and to reveal side effects on a limited scale.

A documented, agreed description of the best current way to perform a task, including sequence, timing and expected results, forming the baseline against which improvements are held.

A document that states which measures will be monitored after the project, how often, by whom, and what action to take when results drift outside the expected range.

A run chart with statistically calculated limits that helps distinguish normal variation from special causes, signaling when a process has changed and needs investigation.

A practice of continuous, often small improvement carried out by the people who do the work, aiming to make many incremental gains rather than waiting for one large breakthrough.

A workplace organization method with five steps: sort, set in order, shine, standardize and sustain. It reduces searching, clutter and errors so work can be done consistently.

A small group of people with complementary knowledge who share a common improvement goal, clear roles and regular communication, and who are jointly accountable for results.