Lean Six Sigma Glossary

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3M (Muda, Mura, Muri)A concept used in Lean that refers to three types of waste: Muda (non-value-adding work), Mura (inconsistency), and Muri (overburden). These are often targeted for elimination in Lean methodologies.
3P Lean MethodThe 3P stands for “Production Preparation Process.” It is a method used in Lean manufacturing to design or re-design a workplace layout to optimize its efficiency and productivity.
5 WhysA problem-solving technique that involves asking “Why?” five times consecutively to drill down to the root cause of a problem. By repeatedly asking the question, the cause-and-effect relationship of the issue is explored.
5M (Man, Machine, Material, Method, Measurement)A cause-and-effect analysis tool used to investigate the potential root causes of a problem by exploring the five major categories. It’s often used in conjunction with a fishbone (Ishikawa) diagram.
5S5S represents five steps: Sort, Set in order, Shine, Standardize, and Sustain. It’s a workplace organization technique used in Lean manufacturing to create a clean, organized, and efficient workspace.
5S auditA 5S Audit is the process of evaluating how well a business or workplace is implementing the 5S principles. It aims to identify areas of improvement and ensure consistent adherence to the 5S methodology.
5S Red Tagging5S Red Tagging is a technique used during the Sort phase of 5S. Items that are not immediately necessary are tagged with a red label and moved to a designated area to decide their fate – whether to keep, discard, or relocate.
5W1H Is/Is Not Problem Definition5W1H stands for “Who, What, Where, When, Why, and How.” The “Is/Is Not” technique helps define a problem by detailing what it is and what it is not. This provides clarity and narrows down the root cause.
8 Step TrainingA methodology that breaks down training into eight steps. It’s designed to ensure effective and consistent training across an organization.
8 WastesIn Lean manufacturing, the 8 Wastes refer to eight common inefficiencies in a process: Defects, Overproduction, Waiting, Not utilizing talent, Transportation, Inventory excess, Motion waste, and Excess processing.
8D Problem Solving8D stands for “8 Disciplines.” It’s a systematic problem-solving methodology that involves eight steps: Define, Form a team, Describe the problem, Contain, Root cause analysis, Choose and verify solutions, Implement solutions, and Celebrate.


A3 Problem SolvingA structured problem-solving and continuous improvement approach, named after the international paper size it’s traditionally written on (A3). This method focuses on root cause analysis and systematic problem resolution using a single sheet of paper.
ABC AnalysisA method of classifying items based on their significance. Often used in inventory management, items are categorized as ‘A’ being the most important, ‘B’ being of moderate importance, and ‘C’ being the least important.
Activity Network DiagramA diagram used in project management to depict the sequence of activities in a project. It helps in identifying the critical path, which is the longest sequence of activities that must be completed on time for the project to be finished on the due date.
Actual Cost (AC)In project management, it refers to the actual expenses incurred for work performed on an activity during a specific time period. It’s often compared with the estimated cost to measure performance and forecast future costs.
ADKAR Change ManagementA goal-oriented change management model that stands for Awareness, Desire, Knowledge, Ability, and Reinforcement. It outlines the five outcomes an individual needs to achieve for a change to be successful.
Affinity DiagramsA tool used to organize data and ideas into related groups. Often used after brainstorming, it helps in clustering data points or ideas into themes or categories.
Agile Project ManagementA project management and product development methodology that prioritizes flexibility, collaboration, and customer feedback. It involves iterative progress, team collaboration, and flexibility to changing requirements.
AlignmentEnsuring that everyone in an organization understands and is committed to its strategic goals. In Lean Six Sigma, alignment often refers to ensuring that improvement projects and initiatives support the overall business strategy.
AndonA visual alert system, often in the form of a light or signboard, used in manufacturing. It signals quality or process problems in real-time, prompting immediate attention.
ANOVA (Analysis of Variance)A statistical method that evaluates the differences between group means in a sample. It’s used to determine the impact of one or more variables on a dependent variable.
Attribute Agreement Analysis (AAA)A statistical method used in quality control to assess the agreement or consistency of evaluations made by different appraisers examining the same sample. It’s used to determine if there’s a standard consensus among the evaluators.
Autonomous MaintenanceA foundational element of Total Productive Maintenance (TPM). It empowers machine operators to take care of their equipment, performing routine checks, minor repairs, and basic maintenance tasks.


Balanced ScorecardA performance metric used in strategic management to identify and improve various internal functions and their resulting external outcomes. It balances financial measures with performance measures related to a company’s critical success factors.
BaselineA reference point used for comparison. In project management and quality improvement, a baseline often refers to the current state before changes or improvements are made, providing a “before” snapshot that can be compared to future results.
Batch ProcessingA method of producing goods or processing data in large groups or batches rather than in a continuous stream. It’s a common way to handle large volumes but can sometimes introduce delays.
BenchmarkingThe process of comparing one’s business processes and performance metrics to industry bests or best practices from other industries. It identifies where gaps in performance reside and provides insights into areas of improvement.
Benefit-Cost Ratio (BCR)An indicator, used in the formal discipline of cost-benefit analysis, which attempts to summarize the overall value for money of a project or proposal. A BCR value of greater than 1.0 indicates a potentially positive investment, while a value of less than 1.0 indicates a potentially negative investment.
Black BeltIn the context of Lean Six Sigma, a Black Belt is a professional who is well-versed in the Lean Six Sigma methodology and leads complex improvement projects, typically full-time.
BottlenecksPoints in a process where the flow of operations is slowed down, or capacity is exhausted due to limitations. Bottlenecks can hinder productivity and efficiency, leading to delays and potential backlog.
Box and Whisker Plots (Excel)Similar to the manual version, this is a graphical representation of data dispersion and skewness, created using Microsoft Excel’s functionalities.
Box and Whisker Plots (Manual)A graphical method to depict groups of numerical data through quartiles. The ‘box’ shows the interquartile range, and the ‘whiskers’ represent variability outside the upper and lower quartiles. This manual version refers to plots made without software.
BrainstormingAn ideation method where a group of people come together to generate solutions to a specific problem. It encourages free thinking and all ideas, even unconventional ones, are welcome.
Break-Even AnalysisA financial calculation that determines how many products or services need to be sold to cover costs, particularly fixed costs. It’s the point at which there’s neither profit nor loss.
Business Process MappingA visual representation of a process, showing the sequence of tasks, to understand and improve its flow. It provides insights into potential inefficiencies, redundancies, or areas of improvement within the process.



Cause and Effect DiagramAlso known as the Ishikawa or fishbone diagram, it’s a tool used to identify and visually display the potential causes of a specific problem or issue. It helps in root cause analysis by categorizing potential causes into groups.
Chi-Square TestA statistical test used to determine if there’s a significant association between two categorical variables. It compares observed frequencies with expected frequencies to test hypotheses.
Confidence IntervalsA range of values used in statistics to estimate the true population parameter. It provides an interval estimate of a parameter and indicates the reliability of the estimate.
Continuous ImprovementA philosophy and ongoing effort to improve products, services, or processes over time. In Lean and Six Sigma, it involves making incremental improvements to reduce waste and improve efficiency and quality.
Control ChartsAlso known as process behavior charts, they are tools used in quality control to determine if a manufacturing or business process is in a state of control. It visualizes data over time, with upper and lower control limits.
Control PlanA detailed plan that describes actions required at various stages of a process to ensure that process outputs are within specified limits. It’s used in Six Sigma projects to monitor and maintain the improved process.
Cost of Poor Quality (COPQ)The costs associated with producing defective goods or providing substandard services. It includes costs related to rework, scrap, warranty claims, returns, and other related expenses. COPQ is used in Six Sigma to quantify the impact of defects and inefficiencies.
Corrective and Preventive Actions (CAPA)A systematic approach used by organizations to identify and correct the root causes of problems or incidents and prevent their recurrence. CAPA is a critical aspect of quality management in various sectors, especially in regulated industries.
Critical Path Method (CPM)A project management technique used to determine the sequence of activities that represents the longest path through a project. It identifies the shortest possible duration required to complete a project without delaying it.
Critical to Quality (CTQ) TreeA tool used in Six Sigma to translate customer needs and requirements into measurable characteristics for a product or process. It breaks down broad categories into specific elements that can be addressed and improved.
Cross-Functional TeamA group of people with different functional expertise, often from different departments, who collaborate toward a common objective. They provide diverse perspectives and are particularly useful in complex projects or problem-solving scenarios.
Cycle TimeThe total time from the beginning to the end of a process, including both work time and wait time. It’s used in Lean to measure how long it takes for an item to pass through a process or system.


Data CollectionThe systematic gathering and measurement of information from various sources to get a clear and detailed view of an area of study. It’s an essential process in Six Sigma projects to inform decision-making and validate changes made to a process.
Data StratificationThe process of dividing a dataset into smaller sub-sets based on specific criteria, such as product type, supplier, or time period. It helps in identifying patterns or trends that might be hidden in the aggregated data.
Decision MatrixA tool used to evaluate and prioritize a list of options. It involves listing options and setting criteria for evaluation. Scores are assigned based on the criteria, and the options are ranked to aid decision-making.
DefectAny product or service characteristic that doesn’t meet customer specifications or requirements. In Six Sigma, the aim is often to reduce the defect rate to improve quality.
Defect OpportunityAny event where a defect might occur during the operation of a process. In Six Sigma, it’s used to calculate DPMO by identifying the number of opportunities for a defect to happen.
Deployment FlowchartA type of process map that shows the flow of a process across different departments or areas of a business. It helps in identifying bottlenecks, redundancies, and areas of responsibility.
Design Failure Mode and Effects Analysis (DFMEA)A systematic, proactive tool used to evaluate a product design for potential failure modes and their impact on product functionality. It identifies where and how a product might fail, assesses the risks associated with those failure modes, and prioritizes the issues for corrective action.
Design for Six Sigma (DFSS)An approach used to design or redesign a new product or service from the ground up. Unlike DMAIC, which focuses on improving existing processes, DFSS focuses on creating new processes or products that achieve Six Sigma quality levels from the start.
DOE (Design of Experiments)A systematic method to determine the relationship between factors affecting a process and the output of that process. It helps in identifying the variable interactions and is used in Six Sigma projects to optimize processes.
DMAICAn acronym for the five-phase approach used in Six Sigma for process improvement. The phases are Define, Measure, Analyze, Improve, and Control. Each phase involves specific steps and tools to drive process improvements.
DMAOVAn extension of DMAIC, it stands for Define, Measure, Analyze, Optimize, and Validate. It’s used for projects that aim to design new processes or products at Six Sigma quality levels.
DRIVE MethodologyA problem-solving methodology that stands for Define, Review, Identify, Verify, and Execute. Similar to DMAIC, DRIVE is a structured approach to process improvement, but it’s more simplified and often used for quick wins or less complex projects.
DPMOStands for “Defects Per Million Opportunities.” It’s a Six Sigma metric used to measure the efficiency of a process. DPMO provides insight into the performance by indicating the number of defects in a process per one million opportunities.
Dynamic Process ControlA methodology that focuses on monitoring and adjusting processes in real-time to ensure they stay within specified control limits. It helps in catching and correcting issues immediately, rather than after the fact.


Eisenhower MatrixA time management tool used to prioritize tasks based on their urgency and importance. It divides tasks into four categories: urgent and important, not urgent but important, urgent but not important, and neither urgent nor important. This helps in determining what needs immediate attention, what to schedule, what to delegate, and what to eliminate.
Error-Proofing (Poka-Yoke)A Japanese term which translates to “mistake-proofing.” It’s a mechanism in lean manufacturing to prevent errors by designing the manufacturing process, equipment, and tools in a way that an operation can’t be performed incorrectly. It aims to eliminate defects by preventing human errors before they occur.
Enterprise Resource Planning (ERP)A suite of integrated applications used by organizations to manage day-to-day business activities, such as procurement, project management, operations, financials, and more. ERP systems provide a centralized database for all business processes to enhance the flow of data across the organization.
Empirical DataInformation obtained by observation or experimentation. In the context of Six Sigma and other data-driven methodologies, empirical data provides a factual basis for decision-making and is collected through direct observations or measurements.
Event SimulationA technique used to model the possible outcomes of an uncertain process or system over time. In Six Sigma, it’s often used to predict the potential impact of process changes.
Exponential SmoothingA time series forecasting method used to analyze data points by creating a series of averages. It’s especially useful when making short-term predictions. In Lean Six Sigma, it can be applied to forecast demand, sales, inventory levels, and more.
External Failure CostsCosts associated with defects that are found after the product is delivered to the customer. This includes warranty claims, returns, recalls, and other related costs. In Six Sigma, the goal is to reduce these costs by identifying and resolving defects earlier in the process.
Exploratory Data Analysis (EDA)An approach to analyzing datasets to summarize their main characteristics, often using visual methods. EDA is used in Six Sigma and other methodologies to understand the structure of the data, identify anomalies, and extract valuable insights before applying formal modeling techniques.


FIFO (First In, First Out)An inventory management and valuation method in which the items produced or acquired first are sold or disposed of first. It ensures that older inventory is used before newer inventory, which is crucial for perishable goods.
Fishbone DiagramAlso known as the Ishikawa or cause-and-effect diagram, it’s a tool used to identify and visually display the potential causes of a specific problem or issue. It helps in root cause analysis by categorizing potential causes into groups, resembling the shape of a fishbone.
Five WhysA problem-solving technique that involves asking “Why?” five times consecutively to drill down to the root cause of a problem. By repeatedly asking the question, the cause-and-effect relationship of the issue is explored.
FlowIn Lean Six Sigma, flow refers to the smooth and uninterrupted movement of products, services, or information through a process. The goal is to reduce delays, wait times, and bottlenecks to ensure a steady and efficient flow.
FMEA (Failure Modes and Effects Analysis)A systematic, step-by-step approach for identifying all possible failures in a design, manufacturing process, or product. It’s used to prioritize the potential failures based on their impact and likelihood of occurrence to improve product or process reliability.
Full Factorial DesignA type of experimental design in which experiments are conducted for all possible combinations of the factors. It provides comprehensive data but can be time-consuming and resource-intensive. Used in Six Sigma projects to understand the effect of multiple factors on a process.
Functional FlowchartA type of flowchart that displays the process flow across different functions or departments. It provides a holistic view of how a process interacts with various functions in an organization and helps in identifying bottlenecks or inefficiencies at the functional level.
Fundamentals of Lean Six SigmaThe core principles and methodologies that underpin the Lean Six Sigma approach. It combines the waste-reducing principles of Lean with the variability-reducing methods of Six Sigma to improve process efficiency, customer satisfaction, and bottom-line results.


Gage R&R (Gage Repeatability & Reproducibility)A statistical tool used in quality control to assess the amount of variation in the measurement system arising from the measurement device and the individuals taking the measurement. It helps ensure that the measurement system is reliable and can accurately measure the process variation.
Gantt ChartA type of bar chart that represents a project schedule. It displays the start and finish dates of the various elements of a project. Gantt charts are useful for tracking progress and ensuring that tasks are completed on time.
Gemba (or Genba)A Japanese term that means “the real place.” In Lean, it refers to the place where value is added, such as the shop floor in manufacturing. The idea is to observe processes at the source to identify wasteful activities or areas for improvement. Gemba walks involve managers visiting the workplace to observe and engage with the frontline workers.
Graphical AnalysisThe use of graphs, plots, and charts to visualize data and identify patterns, trends, and outliers. It’s an essential component of the Analyze phase in DMAIC and helps in understanding the behavior of variables and their relationships.
Green BeltA professional who has been trained in Lean Six Sigma methodologies and tools and can lead or support improvement projects. Green Belts typically work on projects part-time under the guidance of a Black Belt or Master Black Belt.
Gross Process Cycle TimeThe total time taken for a product or service to pass through a process, from the start to the finish, including both value-added and non-value-added activities. It’s used in Lean to identify opportunities for reducing delays and improving process flow.


Heijunka: a lean manufacturing technique that involves leveling production to match customer demand, in order to reduce waste and variability.
Hoshin Kanri: a strategic planning and deployment method that involves setting long-term goals and developing action plans to achieve them.






Jidoka: a lean manufacturing technique that involves stopping the production process as soon as a problem or defect is detected, in order to prevent the production of defective products.
Just-in-time (JIT) manufacturing: a production system that aims to minimize waste and improve efficiency by producing and delivering products just in time for customer demand.



Kaizen culture: a corporate culture that values continuous improvement and encourages all employees to actively participate in the improvement process.
Kaizen event: a structured improvement event that brings together a team of employees to focus on a specific process or problem and identify and implement improvements.
Kaizen: a Japanese term that means “improvement” or “change for the better.” It refers to the continuous effort to improve processes, products, and services, often through small, incremental changes.
Kanban board: a visual board that shows the status of tasks or materials in a process, using cards or other visual indicators.
Kanban signaling: the use of visual signals, such as cards or bins, to indicate the need for materials or products and to track the progress of work through a process.
Kanban: a visual system for managing the flow of materials and information through a process. It uses cards or other visual indicators to signal the need for new materials or products and to track the progress of work through the process.
KPI (key performance indicator): a metric that is used to measure the performance of a process or organization.



Lead time: the time it takes to complete a task or process, from start to finish.
Lean manufacturing system: a production system that is based on lean principles, with a focus on reducing waste, increasing efficiency, and improving quality.
Lean manufacturing: the application of lean principles to the manufacturing industry, with a focus on reducing waste, increasing efficiency, and improving quality.
Lean methodology: the structured approach to continuous improvement that is based on the principles of lean thinking.
Lean principles: the guiding principles of lean thinking, which include a focus on value, the elimination of waste, continuous improvement, and respect for people.
Lean Six Sigma: a combination of lean and Six Sigma methods, with a focus on identifying and eliminating waste and defects in a process to improve efficiency and quality.
Lean startup: an entrepreneurial approach that uses lean principles to quickly develop and test a product or service, and then scale it up if it is successful.
Lean tools: specific techniques and tools that are used to identify and eliminate waste in a process, such as value stream mapping, 5S, and kanban.
Lean: a methodology for reducing waste and increasing efficiency in a production process. It involves identifying and eliminating non-value-added activities and streamlining the remaining activities to create a more efficient process.



Non-value-added activity: an activity that does not directly contribute to the value of a product or service for the customer, but is necessary for the production process.



OEE (overall equipment effectiveness): a measure of how effectively a piece of equipment is being used, calculated as the product of availability, performance, and quality.
One-piece flow: a production approach that involves producing one unit at a time and moving it immediately to the next operation, in order to minimize waste and improve flow.



PDCA (plan-do-check-act): a continuous improvement methodology that involves planning a change, implementing it, checking the results, and then either continuing with the change or returning to the planning stage.
PDCA cycle: the cycle of continuous improvement that involves planning a change, implementing it, checking the results, and then either continuing with the change or returning to the planning stage.
Poka-yoke: a Japanese term that means “mistake-proofing.” It refers to the use of simple, low-cost devices or techniques to prevent mistakes or errors in a process.
Process improvement: the systematic effort to identify and eliminate waste and inefficiencies in a process.
Process mapping: a visual representation of a process that shows the steps involved, the inputs and outputs, and the relationships between the different steps.
Pull system: a production system that is triggered by customer demand, rather than being driven by a predetermined schedule.



Quality circle: a small group of employees who meet regularly to identify and solve problems in their work area.



Root cause analysis: a problem-solving method that involves identifying the underlying causes of problems or defects in a process. The goal is to identify and fix the root cause of the problem, rather than just addressing the symptoms.



Single-minute exchange of dies (SMED): a methodology for reducing the time it takes to changeover a production process from one product to another. It aims to reduce setup times to less than 10 minutes.
SIPOC (suppliers, inputs, process, outputs, customers): a visual representation of a process that shows the relationships between suppliers, inputs, the process itself, outputs, and customers.
Six Sigma: a methodology for identifying and eliminating defects in a process. It uses statistical analysis and process improvement techniques to identify and eliminate the root causes of defects, with the goal of achieving a process that is 99.99966% error-free.
Standard operating procedure (SOP): a written document that describes how a task should be performed, including the necessary steps, the sequence in which they should be performed, and any relevant standards or targets.
Standard work: a documented process that defines the most efficient and effective way to perform a task. It includes the necessary steps, the sequence in which they should be performed, and any relevant standards or targets.
Standardized work: documented processes that define the most efficient and effective way to perform a task.



TAKT time: the rate at which a product must be produced in order to meet customer demand.
Theory of constraints (TOC): a management approach that focuses on identifying and addressing bottlenecks or constraints in a process in order to improve overall performance.
Throughput: the rate at which a process produces output, measured in units per time period.
Total quality management (TQM): a management approach that focuses on continuous improvement and customer satisfaction by involving all employees in the quality improvement process.
TPM (total productive maintenance): a maintenance approach that involves involving all employees in the maintenance process and focusing on maximizing the overall productivity of a piece of equipment.




Value stream mapping: a visualization tool that helps to identify and eliminate waste in a process by mapping out the flow of materials and information from the beginning to the end of the process.
Value-added activity: an activity that directly contributes to the value of a product or service for the customer.
Visual control: the use of visual aids and displays to help workers quickly and easily understand and control a process.
Visual management: the use of visual aids and displays to help workers quickly and easily understand and control a process.
VSM (value stream mapping): a tool used to identify and eliminate waste in a process by mapping out the flow of materials and information from the beginning to the end of the process.



Waste reduction: the systematic effort to identify and eliminate waste in a process in order to improve efficiency and reduce costs.
Waste walk: a structured walk-through of a process or workplace to identify and eliminate waste.
Waste: any activity or material that does not add value for the customer and consumes resources without contributing to the final product or service.
Workflow: the series of tasks and activities involved in producing a product or providing a service.
Work-in-process (WIP): materials or products that are being processed or worked on but are not yet finished or complete.
Workstation: a place where work is performed, often consisting of the tools, equipment, and materials needed to perform a specific task.




Yield: the percentage of units produced that meet the required quality standards.