Symbols & Numbers

You have discovered one of the most comprehensive Lean Six Sigma glossaries available. Here you will find Lean, Six Sigma and other Continuous Improvement terms and definitions. Please feel free to refer back to this glossary as you move forward with your Continuous Improvement efforts. Also, please feel free to contact us if you have questions or would like to see other words added to the glossary.


Abnormality Management

Being able to see and quickly take action to correct abnormalities (any straying from Standard Work). This is the goal of standardization and visual management. Continuous waste elimination and problem solving through kaizen are only possible when the abnormalities are visible.


Instrument accuracy is the difference between the observed average value of measurement on a test piece or process, and the master value for the same test piece or process

Activity Based Management  – ABM

Activities managed based on ABC costing.

Activity Based Costing – ABC

A management accounting system that assigns cost to products based on the resources used to perform a process (design, order entry, production, etc). These resources include floor space, raw materials, energy, machine time, labor, etc.

Affinity Diagram

A process to organize information by placing it on cards and grouping the cards that go together in a creative way. Header cards are then used to summarize each group of cards.

Alternate Hypothesis

A hypothesis which one is trying to prove.  Contrast to Null Hypothesis

Andon A system of flashing lights used to indicate production status in one or more work centers; the number of lights and their possible colors can vary, even by work center within a plant; however, the traditional colors and their meanings are:

green – no problems

yellow – situation requires attention

red – production stopped; attention urgently needed

Andon Board

A visual control device in a production area, typically a lighted overhead display or board. Andons are used to give the current status of the production system and alert team members to emerging problems or abnormal situations.


Analysis of Good – Analysis technique to sort data from best to worst to identify visual trends in the test matrix.


Analysis of Means – Analogous to ANOVA only looking at the difference of Means, usually in a graphical format.


Analysis of Variance – a basic statistical technique for analyzing experimental data.  It subdivides the total variation of a data set into meaningful component parts associated with specific sources of variation in order to test a hypothesis on the parameters of the model or to estimate variance components.  There are three models; fixed, random and mixed.


Annual Operating Plan – Basically plan that a site/SBU/SBE is measured to.


Acceptance Quality Level – when a continuing series of lots is considered, a quality level that, for the purposes of sampling inspection, is the limit of a satisfactory process average.

Attribute Data

Typically go / no-go information (yes/no, good/bad…).  The control charts based on attribute data include percent chart, number of affected units chart, count chart, count per unit chart.


“Automation with a human touch”.  A system in which machinery automatically inspects each item after processing it and ceases production if a defect is detected.

 (English translation of Jidohka) – a form of automation in which machinery automatically inspects each item after producing it, ceasing production and notifying humans if a defect is detected; Toyota expands the meaning of jidohka to include the responsibility of all workers to function similarly, i.e. to check every item produced and to make no more if a defect is detected, until the cause of the defect has been identified and corrected.

Average Chart

A control chart in which the subgroup average, X-bar, is used to evaluate the stability of the process level.



The process of automatically decrementing perpetual inventory records, based on the bill of materials of a given product. Normally triggered by shipment and invoicing to a customer, back flushing is used to eliminate wasteful inventory transactions.

Balanced Plant

A plant where capacities of all resources are balanced exactly with market demand

Balanced production

All operations or cells produce at the same cycle time. In a balanced system, the cell cycle time is less than takt time.

Barriers to Flow

Flow is a primary objective of Lean.  Barriers to flow can be seen as process steps or any of the 6M’s that are restricting flow.  Examples include: inventory, approvals, inspections, batching, long set-up times…

Batch Production

A “Push” system of production where resources are provided to the consumer based on forecasts or schedules. This is not Lean.


Producing more than one piece of an item and then moving those items forward to the next operation before that are all actually needed there. Thus, items need to wait in a queue. This is not Lean.


Black Belt or Black Belt Candidate


The process of measuring products, services, and practices against those of leading companies.  Then learning and applying their best practices to see similar improvements.


A best-known example of performance in a particular operation. One needs to define both the class and the operation to avoid using the term loosely


The difference between the observed mean reading and reference value.


A blitz is a fast and focused process for improving some component of business a product line, a machine, or a process. It utilizes a cross-functional team of employees for a quick problem-solving exercise, where they focus on designing solutions to meet some well-defined goals.


Between Mean Square – used in the Interclass Correlation Coefficient


Any process step that limits throughput of the entire process.  See Constraint

Breakthrough objectives

In Policy Deployment, those objectives characterized by multi-functional teamwork, significant change in the organization, significant competitive advantage and major stretch for the organization.





Change Over time.  See Setup Time


See Cycle Time

Capacity Constraint Resources

Where a series of non-bottlenecks, based on the sequence in which they perform their jobs can act as a constraint.

Cause and effect Diagram

A problem-solving tool used to establish relationships between effects and multiple causes.  The effect is identified with branches (fish bones) showing many causes for the effect.

Cause and Effect Matrix

A tool for analyzing a process whereby the cause and effect are ranked by severity to the customer, as well as the possible occurrence of the cause in the process.  This is then multiplied and added by process step and ranked to help focus efforts to process improvements.  This is a precursor to the FMEA in some cases.

Cellular layout

The layout of machines of different types, performing different operations in the sequence of processing to permit single-piece flow and flexible deployment of human effort to operate multiple machines.   Contrast to functional layout.

Central Limit Theorem

Any given distribution (even non-normal data) approaches a normal distribution as the sample size increases.  The central limit theorem explains why many distributions tend to be close to the normal distribution.


Helps the organization apply concepts and overcome barriers.

Changeover Time

See Setup Time

Common Cause Variation

Causes of variation that are inherent in a process over time.  Common cause variation is fluctuation caused by unknown factors (see 6M’s) resulting in a steady but random distribution of output around the average of the data. It is a measure of the process potential, or how well the process can perform when Special Cause Variation is removed. Also known as “Random Variation”.


Two or more effects that cannot be separated.  Usually a result of running less than a full factorial designed experiment.


Anything that limits a system from achieving higher performance or throughput also known as a bottleneck.

Continuous Flow Production

Each process makes only the one piece that the next process needs. Requires effective Setup Time Reduction. Also called single piece flow, one piece flow and make one pass one.

Continuous Improvement (CI)

The never-ending process of eliminating waste and reducing variation.

Control Chart

A chart with upper and lower control limits on which values of some statistical measure for a time series of samples or subgroups is plotted.  The chart frequently shows a central line to help detect a trend of the plotted values toward either control limit.  Could be I-mR or Xbar-mR

Control Element

A specific process variable, which must be controlled. Measurements of a control element indicate whether or not a stable condition has been achieved


Cost of Poor Quality; the cost of failing to produce & deliver 100% quality to our customers.  Includes internal, external, inspection, prevention and missed opportunity.

Counter measures

Immediate actions taken to bring performance that is tracking below expectations back into the proper trend. Requires Root Cause Analysis

Counterclockwise flow

A basic principle of Lean manufacturing cell layout is that the flow of material and the motion of people should be from right to left, or counterclockwise. The origin of this idea came from the design of lathes and machine tools with the chucks on the left side, making it easier for right-handed people to load from right to left.


Components Of Variation – an analysis of nested factors using a control chart methodology to determine the greatest source of variation.


The impact of one variable upon others in the same group


Process Capability target centered in specification range, compares the amount of common cause variation that exists in the process to that allowed by the specification, expressed as: glossformula2


Process Capability, target not centered on range but on specification target, or one side only expressed as:  minimum of glossformula1

Criteria Selection Matrix

A tool utilized to prioritize and select from a large collection of possible choices.

Critical Input

In Process Mapping – Input variables that have been statistically shown to have a major impact on the variability of the process output variable(s).

Crossed Factors

These are factors that are independent from each other, that is they may be adjusted and run in an experiment in any order necessary.


Completely randomized replicate – A replicate that has all runs randomized across the experiment in a DOE


Customer Satisfaction Index – A measure of customer’s delight with your product or service.

Current State Map

Current state value stream maps show “as is” flow of information and flow of product/service.  It identifies opportunities for improvement.

Cycle Time

The time it takes to do one repetition of any particular task at an individual process step. Cycle time can be categorized into 1) manual cycle time, 2) machine cycle time, and 3) auto cycle time. Also referred to as touch time or process time.


Daily Management

Attention each day to those issues concerned with the normal operation of a business.

Days supply of inventory (DSI)

Total number of days (if the production level equals zero) that it would takes to deplete finished goods inventory for the specified product line based on customer demand.


One of the 8 wastes.  Any activity, service or product that is not done right the first time.

Deming Cycle

The concept of continuously rotating wheel used by W. E. Deming to emphasize the necessity of constant interaction among research, design, production, and sales so as to arrive at an improved quality that satisfies customers (see PDCA Cycle)

Dependent Events

Events that occur only after a previous event.


See Detectability


Used in the FMEA to rate the ability to detect the cause of a failure mode.  Also known as Detection.


Degrees of Freedom – The number of independent pieces of information that can be used to estimate a statistic. We earn one df for every data point we take and we use one up for every statistical parameter we estimate.  The more df’s we have in a sample the closer we come to a normal distribution


Design for Manufacturability – Involves a team effort of product design, production knowledge, Engineering…to develop product which can be produced in the most efficient way.


Technological ability of the measurement system to adequately differentiate between values of a measurement parameter.


The basic model for Six Sigma.  Involves: Define, Measure, Analyze, Improve & Control


Design Of Experiment – Statistically planned experimental exploration and/or confirmation of critical inputs from the FMEA, multi-vari study or process map.


Defects per Million Opportunities – a measure of the potential for a defect, also used to convert into a Sigma for the process, a measure of quality of the process.


Defects per Unit – Any time a customer requirement is not met, sometimes known as escapes.


The inherent shift of a process, measurement, or statistic over a period of time.


Days Sales Outstanding – a measure of lack of cash flow.


Error Proofing

See Mistake Proofing

Every part every (EPE)

Measured in terms of time (hours, days, weeks, months, etc.) “Every Product Every X” indicates the level of flexibility to produce whatever the customer needs. For instance, Every Product Every day would indicate that changeovers for all products required can be performed each day and the products can be supplied to the customer



Independent and controllable variables which can change the output of a process utilized in DOE.

Failure Effect

From an FMEA – What the effect will be to other functions, systems, customers etc.

Failure Mode

From an FMEA – Ways in which the process is expected to fail to perform.


A lane where material is fed in and pulled out as a “first-in first-out”.  A maximum quantity predetermined and designed to allow only the maximum into the lane.

Fishbone Diagram

See Cause and Effect Diagram

Fixed Effects Model

A situation where a model is generated from the glossu or glosssigma for fixed factor levels.

Fixed Factors

The levels of the factors used in an experiment were the specific levels are of interest.

Flexible Manufacturing System (FMS) An integrated manufacturing capability to produce small numbers of a great variety of items at low unit cost.  An FMS is also characterized by low changeover time and rapid response time.


A main objective of the lean production effort, and one of the important concepts that passed directly from Henry Ford to Toyota. Ford recognized that, ideally, production should flow continuously all the way from raw material to the customer and envisioned realizing that ideal through a production system that acted as one long conveyor.  Also see Barriers to Flow

Flow Chart

A problem solving tool that illustrates a process. It can show the “as is” process or “should be” process for comparison and should make waste evident


Failure Modes and Effects Analysis – Systematic method for documenting potential failure modes, determining effects, identifying causes of failures, developing plan, team concurrence, and take action.


First Pass Yield – the percentage of parts that went through a process step without a defect.

Fractional Factorial

A DOE where all factors are varied, but not all combinations of the factors are run over the experiment.

f-test A test to statistically prove there has been a significant shift in the standard deviation from data set to another.

During process improvement, this test can demonstrate that you have reduced variation from an old process to the new process.

Full Factorial

A DOE where all factors are varied and all combinations of the factors are run over the experiment.

Functional Layout

The practice of grouping machines or activities by type of operation performed. This is generally not considered Lean.

Future State Map

Future state value stream maps show “to be” flow of information and flow of product or service.  It includes a redesign of the Current State Map integrating Lean concepts to achieve a desired performance.


Gage R&R

Gage Repeatability & Reproducibility – A method for evaluating the variation in the measurement process.  Allows for comparison, graphically and analytically, of process to measurement and specification to measurement variation.


Green Belt or Green Belt Candidate


Japanese for ‘actual thing’ or ‘actual product’. The tools, materials, machines, parts, and fixtures that are the focus of kaizen activity.


Japanese for ‘the facts’ or ‘the reality’. The actual facts or the reality of what is happening on the shop floor and in the business.



See Alternate Hypothesis


Averaging both the volume and the production sequence of different model types on a mixed-model production line to achieve smooth flow of product or service.

May be found as a schedule board, heijunk box, heijunka wheel, kanban links… In a larger sense, it includes all of the activities around smoothing and sequencing demand.


A chart that displays data in distribution, generally in graph format. It may be used to reveal the variation that any process contains.


See Null Hypothesis

Hoshin Planning

Also known as Management by Policy or Strategy Deployment. A means by which goals are established and measures are created to ensure progress toward those goals. It keeps activities at all levels of the company aligned with its overarching strategic plans.



Interclass Correlation Coefficient – a reliability index that allows you to see how well defined a subjective measurement system is when a ranked scaling is being used.


Individual X Moving Range Chart.  Looks at one piece samples on a Control Chart

Inference Space

Area within which you draw conclusions (e.g., based on the results of a DOE)

Interclass Correlation Coefficient A reliability coefficient that is used to judge the reproducibility of a subjective measurement system for attribute data that is ranked. One type of MSA

One of the 8 Wastes.  All raw materials, purchased parts, work-in-process components, and finished goods that are not yet sold to a customer.

Ishikawa Diagram

See Cause and Effect Diagram



see Autonomation

Just-In-Time (JIT)

A concept of having just the right amount of inventory needed exactly when it is needed to reduce costs associated with holding inventory.  JIT is a system for producing and delivering the right items at the right time, in the right amounts.



Factor – when used in the formula 2Rk-p for defining a fractional factorial.


A rapid and radical change process, sometimes used as a precursor to kaizen activities.  Small incremental improvements


The philosophy of continuous improvement.

Kaizen Blitz

See Kaizen Event

Kaizen Event A focused, structured, short-duration problem-solving activity used to improve processes throughout the organization. Generally ranges from 1 to 5 days.

A signal to the supplying process that the input has been consumed and is ready for replenishment.


A reliability coefficient that is used to judge the reproducibility of a subjective measurement system for attribute data that is non-ranked (ie good/bad, pass/fail…). This is one type of MSA.


Key Process Indicator (index)


Key Process Input Variable


Key Process Output Variable



Lower control limit of a Control Chart calculated based on the average range (within subgroup) and the grand mean (between subgroup) of the data.

Lead-Time The total time a customer must wait to receive a product after placing an order.

Removal of non-value added activities (8 Wastes) resulting in improved delivery of product or service at the most efficient return on investment.

Line Balancing

Balancing of Cycle Times at each operation to be less than or equal to Takt Time.


A measure of deviation from a linear relationship between two variables, or the issue of Linearity, where a measurement system has changing variation across its usable range of measure.


Lower limit of the engineering specification – independent of the control limit of a process.


Maintenance Activities that are directed to maintaining current technological, managerial, and operating standards.

Make One Pass One

See Continuous Flow Production


Master Black Belt or Master Black Belt Candidate


Measure to provide indication of the central tendency of a data set. Sum of all data points divided by the number in sample taken.

Measurement Error

Variation in measurements that can be attributed to variation in the item being measured or in the measurement system itself


Value falling in the middle of a data set when data are sorted in an order, ascending or descending

Metrics Means of showing business process performance.  Can measure inputs (indicators) or outputs.  Should include goals and metric ownership.
Mission Statement Describes a company’s product, market, and technological areas in a way that reflects the values and priorities of the business leaders.  It is “what they do”.
Mistake Proofing Process, equipment, tools… designed not to allow mistakes to occur
Mixed Model Production Capability to produce a variety of models, that differ in labor and material content, on the same production line.  Allows for efficient utilization of resources while providing rapid response to marketplace demands.
A shared resource that can only be used by one requester at a time. Typically, a large and/or expensive tool or machine. It could also be a person or department that is shared by multiple requesters. A monument is not necessarily a bottleneck or a constraint if it has the capacity to quickly meet demand. At the monument it’s critical to schedule and align requesting demand that is placed on the monument. Examples of monuments: a shared color copier, one paint booth, only one forklift in a warehouse, only one person who has the authority to approve, only one phlebotomist to serve all patients, etc.
Motion (excessive)

One of the 8 Wastes.  Any motion not needed to add value to product or service.


Moving Range


Measurement System Analysis – Identification and quantification of the different sources of variation that are caused by and affecting the measurement system.


Mean Time Between Failure – Common equipment reliability measure looking at the average time between failures.


Mean Time to Repair – Looks at the average time to perform equipment repairs.


Japanese for waste.  Any activity that adds to cost without adding to value of the product. The seven original wastes.  See the first seven of the 8 Wastes.

Multi-Skilled Worker People at any level of the organization that are diverse in skills and training. They provide the organization with flexibility and grow in value over time. Essential for achieving maximum efficiencies of Lean.
Multi-Variable Chart

A multi-vari chart is a tool that graphically displays patterns of variation. It is used to identify possible inputs or families of variation, such as variation within a subgroup, between subgroups, or over time.


Japanese for inconsistency or unevenness.  Variations in process quality, cost and delivery

Muri Japanese for unreasonableness.  Demand exceeds capacity.



Sample Size


Numerical Evaluation of Metrics – another name for control charting focusing on the idea rational subgrouping, that is using changing subgroups to evaluate a process.


In a multi-factor experiment the levels of one factor (factor B) are similar but not identical for different levels of another factor (factor A).  This hierarchical design is said to have factor B nested under the levels of factor A.


National Institute of Standards


Variables, or factors which are difficult, or not feasible to control, but can be monitored or measured.

Normal Distribution

A bell shaped curve with a single peak, symmetrical about the center (mean), defined by a data set or a population

Null Hypothesis

A statement of no difference between before and after states.  Contrast to Alternate Hypothesis


Non-Value Added – Activities or actions taken that add no real value to the product or service.  See 8 Wastes.



Occurrence – as defined in the FMEA


Overall Equipment Effectiveness –  OEE = (% Available) x (% of designed output rate) x (% First Pass Yield)


One Factor at A Time – holding all factors constant while one factor is changed to see its effect on the output.  This is the lowest level (less efficient) means of DOE.

One-piece flow

See Continuous Flow Production

Operating Expenses The money required the system to convert inventory into throughput
Operational Planning

Tactical details for short-term tied into Strategic Plans


One of the 8 wastes.  Producing more, sooner or faster than is required by the next process.



Product Tolerance from the Gage R&R output – This column shows the percentage of the process tolerance taken up by each variance component.

PACE chart

Tool utilizing quadrants to categorize based on ease of implementation and anticipated benefits.  PACE – Possible, Action, Challenge, Eliminate.  Setting the PACE to great improvements.

Pareto Chart

A vertical bar graph showing the bars in descending order of significance, ordered from left to right. Helps to focus on the vital few problems rather than the trivial many. A majority of the items will be relatively minor in significance, (i.e. the 80/20 rule)

PDCA Cycle

An adaptation of the Deming wheel. While the Deming wheel stresses the need for constant interaction among research, design, production, and sales, the PDCA Cycle asserts that every managerial action can be improved by careful application of the sequence: Plan, Do, Check, Act then recycle back to Plan.


Practical Graphical Analytical – Methodology of analyzing results from a DOE.

Point of Use Storage

Also known as POU.  This concept puts all required material to perform a task with reach of the worker.  A Water Spider replenishes as needed.


See Mistake Proofing

Policy Deployment

See Hoshin Planning


Parts per Million – a measure of defects in a process


See Repeatability

Probability Distribution

Diagram of relative frequency of occurrence for the whole population


The flow of material in time and space. The accumulation of sub-processes or operations that transform material from raw material to finished product

Process Capability

Performance of the process when it is operating in control

Process Capability Index

See Cp and CpK

Process Centering

A method to ensure that the peak of the process output distribution (assuming normality) is at the center of the specification limits.

Process Kaizen

Improvements made at an individual process or in a specific area. Sometimes called “point kaizen”

Process Mapping

Graphical method to describe activities/tasks, sub processes, process boundaries, process flow, and process inputs (x’s & X’s), classification of process inputs (noise, sop, controllable…) and process outputs (y’s & Y’s)

A visual representation of the sequential flow of a process. Used as a tool in problem solving, this technique makes opportunities for improvement apparent.

Process Time

See Cycle Time

Processing (excessive)

One of the 8 Wastes.  Processes that may not be necessary… not adding value.

Production Smoothing

The creation of a level schedule by sequencing orders in a repetitive pattern and smoothing the day-to-day orders to correspond to longer-term demand.  Without level consumption patterns over a defined horizon, kanban pull systems will not work well.  Also known as Heijunka.

Project Charter

A tool utilized at the beginning and through out any project or event to keep teams focused and delivering results.

Pull System

A system of cascading production and delivery instructions from downstream to upstream activities in which the upstream supplier waits until the downstream customer signals a need. A pull system means producing only what has been consumed by downstream activities or customers.  This system minimizes waiting, overproduction and inventory.

Push System

In contrast to the pull system, product is pushed into a process, regardless of whether it is needed. The pushed product goes into inventory, and lacking a pull signal from the customer indicating that it has been bought, more of the same product could be overproduced and put in inventory.  This is not considered Lean.



Quality Function Deployment – a method of evaluating a process and its impact on the customer’s expectation.

A visual decision-making procedure for multi-skilled project teams that develops a common understanding of the voice of the customer and a consensus on the final engineering specifications of the product that has the commitment of the entire team. QFD integrates the perspectives of team members from different disciplines, ensures that their efforts are focused on resolving key trade-offs in a consistent manner against measurable performance targets for the product, and deploys these decisions through successive levels of detail.

Quality Management

The systems, organizations, and tools which make it possible to plan, manufacture, and deliver a quality product or service. This does not imply inspection or even traditional quality control. Rather, it builds quality into the entire process of bringing goods and services to the customer.

Queue Time

The time a product spends in a line awaiting the next design, order processing, or fabrication step

Quick Changeover

See Setup Time Reduction



Range – with regards to subgroups in control charting

R Chart

Range chart – showing the ranges of the subgroups the R Bar and the UCLR

Random Effects Model

A situation where we want to extend the conclusions of a statistical test beyond the levels of the factors used in the test, the factors therefore must be random factor levels from a larger population of potential levels.

Random Factors

In some experimental situations the factor levels are chosen at random from a larger set of potential factor levels.  The intent being to draw conclusions of the larger population of levels of the factor not just those used.

Random Variation

See Common Cause Variation


Difference between the largest data value and the smallest data value, in a subgroup or data set.


A method to evaluate business processes compared to individuals (or functions) with regards to who is; responsible, accountable, supportive, informed and consulted.


Randomized Complete Block Design – Running a DOE with two blocks randomizing within the block.


Root Cause and Corrective Action


Variation between successive measurements of the same part, same characteristic, by the same person using the same instrument (short term variation)


With one set up in a DOE and running multiple parts per treatment to quantify the impact of factors on short term variation, does not add df to the analysis.


Within a DOE the additional run of all treatments to understand the short term to medium term variation usually including multiple set ups.  Adds df to the analysis.


The difference in the average of the measurements made by different persons using the same instrument, but different set-ups, when measuring the identical characteristic


Randomized Incomplete Block Design – Running a DOE with a block within one factors levels sets.


Return on Investment – a financial term to define the value of the decision or project.

Root Cause Analysis

Identifying the “true” reason for a known issue.  5 Why’s, Cause and Effect Diagram and Cause and Effect Matrix are some tools for getting to the root cause.


Rule of Thumb


Risk Priority Number – The product of Severity, Occurrence, Detectability on an FMEA


Rolled Throughput Yield – A measure of a process that looks at the probability of a product going through a process without a defect.  This can be calculated by multiplying the FPY of each process step together.


S Chart

Sample Standard Deviation Chart – used when the subgroups are of unequal sizes in replacement of the R Chart.


Collection of Metrics on one sheet.  Red, yellow and green indicators are utilized for quick and standardize reference.


Statistical Design Methodology – where a tolerance is based on probabilities and definitions of risk rather than worst case scenarios.


One who provides information; a teacher, instructor, or rabbi.

 An outside master or teacher that assists in implementing Lean practices

Setup Time

The time required to change a process over from one product or service type to the next good product or service type.

Setup Time Reduction A process of reducing setup time by identifying and reducing two types of time:

1. Internal Time: Activity that can be done only when the machine or process is not actively engaged in production.  Move as much setup time from internal to external.

2. External Time: Activity that can be performed concurrently with the machine or process performing production duties.


Severity – with regards to the failure effect of an FMEA


A change in of an otherwise stable or steady statistic


Greek letter that represents Standard Deviation.  Also a way of managing a business to collect and use data to “act on fact” in management decisions.

Single Minute Exchange of Dies (SMED)

Changing a die or conducting a model changeover in a less than 10 minutes.  Accomplished through separation of internal and external elements as well as standardizing and practicing the changeover process.  Ultimate goal of changeover times less than or equal to takt time.  Also see Setup Time Reduction

Single Piece Flow

See Continuous Flow Production


Specific, Measurable, Achievable, Relevant, Time Bound – used to define a process improvement projects.


Standard Operating Procedure – See Standard Work.


Safety, Purpose, Agenda, Code of conduct, Expectations, Roles – used to set up the tone of a meeting.

Spaghetti Diagram

Map showing movement of people, product or materials and can show total distance traveled.  Can show multiple people.

SPC – Statistical Process Control 

Statistical charts based on numerical (variable) measurements that become a picture of the process over time.

Special Cause Variation

Variation caused by known factors that result in a non-random distribution of output.  Special cause variation is a shift in output caused by a specific factor (see 6M’s) such as environmental conditions or process input parameters. It can be accounted for directly and potentially removed.  Also known as “Assignable Variation”.


Stability represents variation due to elapsed time. It is the difference between an individual’s measurements taken of the same parts after an extended period of time using the same techniques.


A prescribed documented method or process that is sustainable, repeatable and predictable.  Similar to a rule or law. These involve comparison with accepted norms, such as are set by regulatory bodies.

Standard Deviation

Positive square root of the variance – a measure of the dispersion about the mean of a data set.   Defined by glossformula3 for a sample.

Standard Work

An optimum combination of people, machines (mechanical resources) and material for each task or activity of a process.  See standardization.

A precise description of each work activity specifying cycle time, takt time, the work sequence of specific tasks, and the minimum inventory of parts on hand needed to conduct the activity

Standard Work in Process

The minimum amount of material or a given product, which must be in process at any, time to insure proper flow of the operation


Documenting and using the best known method of completing a task or activity.  Standardization leads to reduced variation leading to more consistent performance in respect to quality, cost and delivery.

The system of documenting and updating procedures to make sure everyone knows clearly and simply what is expected of them.


Strategic planning usually 3 to 5 year forward looking.

Strategic Planning

Sets the direction for long-term business survival.  See Hoshin Planning


Unnaturally small fluctuations on a control chart with an absence of points near the control limits (sometimes termed white space due to lack of points)


A condition where gains made in one activity are offset by losses in another activity or activities, created by the same actions crating gains in the first activity.

Supplier Partnership

An approach to business that involves close cooperation between the supplier and the customer. It provides benefits and responsibilities that each party must recognize and work together to realize
SWOT Analysis An analysis looking at a businesses strengths, weaknesses, opportunities and threats.
System Kaizen Improvement aimed at an entire value stream


Takt Time

Takt Time a measure of how efficient a process is defined as the:

Time Available / Customer Demand.  Takt, is a German term for rhythm. This is NOT the same as Cycle Time.


Total Effective Equipment Productivity – A formula looking at equipment utilization compared to a theoretical capacity.

Theory of Constraints

A lean management philosophy that stresses removal of constraints to increase throughput while decreasing inventory and operating expenses

Throughput time

The amount of time it takes for a product to go through the system, from the first operation to the final operation, including processing, delays, movement, queues, etc.  May be the same as lead-time.

The time required for a product to proceed from concept to launch, order to delivery, or raw materials into the hands of the customer. This includes both processing and queue time.


Three Letter Acronym

Total Defects per Unit (TDU)

Total number of defects in one unit of a product (whether they have been reworked or not during the process).

Total Productive Maintenance

A series of actions designed to insure that every machine or piece of equipment in a production process is always able to perform its required task(s) without interrupting continuous flow of the production process.  TPM attempts to maximize equipment effectiveness (and availability) throughout the entire life of the equipment.

Touch Time

See Cycle Time

Toyota Production System

Manufacturing philosophy that shortens the time between customer order and shipment by eliminating waste


Total Productive Maintenance


Total Production Ratio – Similar to OEE, but not split into three areas of opportunity.


One of the 8 Wastes.  Any transportation of parts, documents and materials from one place to another for any reason.

t-test A test to statistically prove there has been a significant shift in the mean from data set to another.

During process improvement, this test can demonstrate that you have shifted the mean from an old process to the new process.



Upper Control Limit – of a Control Chart calculated based on the average range (within subgroup) and the grand mean (between subgroup) of the data.

Uncoded Matrix

The matrix of factors with their values in actual units (recommendation is to analyze DOE’s with coded factor levels, e.g. –1 & +1)

Underutilization of People

One of the 8 Wastes.  This waste can be seen in two ways: 1) not optimizing peoples time, 2) not utilizing people’s talent, education, skill, experience…


Amount of time a machine can work defined as Total Available time – planned machine down time.


Upper limit of the engineering specification – independent of the control limit of a process.



Value Added – a lean term denoting that an action or process step adds value to the product, value in terms of the customer’s idea of value.


In the Lean sense, it is what the customer wants from you (what they are paying for).

Value Added Process Step
  1. A process step the customer is willing to pay for
  2. A process step the changes or transforms the “thing”
  3. A process step that is done right the first time
Value Chain

Activities outside of your organization that add value to your final product, such as the value adding activities of your suppliers

Value Stream

The specific activities required to design, order and provide a specific product, from concept to launch, order to delivery, and raw materials into the hands of the customer

Value Stream Mapping

Visual flow chart, tracking product and information flow.  Used to map both current and future states with an emphasis on the value add to non-value add ratio of lead-time.

Highlights the sources of waste and eliminates them by implementing a future state value stream that can become reality within a short time

Value-Added Analysis

With this activity, a process improvement team strips the process down to its essential elements. The team isolates the activities that in the eyes of the customer actually add value to the product or service. The remaining non-value adding activities (“waste”) are targeted for extinction


Describes the spread or dispersion of the probability associated with a data set.  Note: you can add variances (normally represented by the Greek letter sigma σ2); you cannot add standard deviations (normally represented by the Greek letter sigma σ).


Description of the ideal state in the future that inspires members of an organization to drive towards excellence.

Visual Control

The placement in plain view of all tools, parts, production activities, and indicators of production system performance so everyone involved can understand the status of the system at a glance. Various tools of visual management such as color-coding, charts, andons, schedule boards, labels and markings on the floor.

Visual Management

System enabling anyone to quickly spot abnormalities in the workplace, regardless of their knowledge of the process


Voice Of the Customer – A feedback loop from customer to supplier.

Desires and requirements of the customer at all levels, translated into real terms for consideration in the development of new products, services and daily business conduct.



One of the 8 Wastes.  Waiting for work, information, approvals, parts, materials, tools, equipment…


Also known as Muda) See 8 Wastes.

Anything that uses resources, but does not add real value to the product or service.

Water Spider A person responsible for replenishing materials located at workstations.  This allows a production worker to stay focused on production reducing barriers to flow.

Within Sample Mean Square – used in the ICC calculation

World Class Manufacturing A philosophy of being the best, the fastest, and the lowest cost producer of a product or service. It implies the constant improvement of products, processes, and services to remain an industry leader and provide the best choice for customers, regardless of where they are in the process.


X, x

Input variable, or factor of a process or a process step.  Sometimes referred to as the independent variable.


X bar (average) moving range chart.  A method of control charting using rational subgroups.


Y, y

Output Variable of a process or process step. Sometimes referred to as the dependent variable. Y’s are the “big” output from the overall process while y’s are the outputs at individual process steps.


With regards to process defined as the percent of product that is good at the end of a process.



Z statistic – transform for normally distributed data.

Symbols & Numbers

glossrbar1 R Bar or average range – with regards to subgroup ranges the average of all ranges in the study.
X Bar defined as the average of X’s in a sample, also known as a sample mean
glossdxbar X Double Bar defined as the average of the averages.
σ See Sigma
Σ Summation – A capital letter of the Greek symbol sigma.
σ Level Sigma Level – A measure of the potential defects of a process.  Used to measure improvement for a defect perspective.
σ2 See Variance
3P Production Preparation Process. Rapidly designing production processes and equipment to ensure capability, built-in quality, productivity, and Takt-Flow-Pull. The Production Preparation Process minimizes resources needed such as capital, tooling, space, inventory, and time.

5 Principals of Lean

  1. Value
  2. Value Stream
  3. Flow
  4. Pull
  5. Perfection

5 Whys

A Root Cause Analysis technique used to identify the true root cause whenever a problem is encountered. This is a simple problem solving method of analyzing a problem or issue by asking “Why?” five times (or a sufficient number of times to get to the true root cause). The root cause should become evident by continuing to ask why a situation exists.


A system for creating and maintaining an organized work place (sort, store, shine, standardize and sustain). Refers to the five words seiri, seiton, seison, seiketsu, shitsuke. These words are shorthand expressions for principles of maintaining an effective, efficient workplace

  • Sort – seiri – eliminating everything not required for the work being performed
  • Store – seiton – efficient placement and arrangement of equipment and material
  • Shine – seison – tidiness and cleanliness
  • Standardize – seiketsu – continually improving seiri, seiton, seison
  • Sustain – shitsuke – discipline with leadership


Man, Machine, Method, Measurement, Material, Mother Nature.  Helps us identify inputs to processes.


Data gathering and analysis tools used for kaizen activities originally by QC Circles. They are 1) check sheets, 2) cause and effect diagrams, 3) Pareto diagrams, 4) histograms, 5) graphs, 6) scatter diagrams, and 7) broken line graphs.

8 Wastes






Motion (excessive)

Processing (excessive)

Underutilization of People (originally started as 7 wastes.  This last one was added over the more recent years)