ASQ Green Belt Exam
Green Belt (GB)
An employee who has been trained in the Six Sigma improvement method at a Green Belt level and will lead a process improvement or quality improvement team as part of his or her full-time job.
leadership
An essential part of a quality improvement effort. Organization leaders must establish a vision, communicate that vision to those in the organization, and provide the tools and knowledge necessary to accomplish the vision.
benefit-cost analysis
An examination of the relationship between the monetary cost of implementing an improvement and the monetary value of the benefits achieved by the improvement, both within the same time period. 562 Glossary
cause
An identified reason for the presence of a defect, problem, or effect.
type II error
An incorrect decision to accept something when it is unacceptable.
type I error
An incorrect decision to reject something (such as a statistical hypothesis or a lot of products) when it is acceptable.
Pp (process performance index)
An index describing process performance in relation to specified tolerance.2
change agent
An individual from within or outside an organization who facilitates change in the organization; might be the initiator of the change effort, but not necessarily.
distribution (statistical)
The amount of potential variation in the outputs of a process, typically expressed by its shape, average, or standard deviation.
quality management (QM)
The application of a quality management system in managing a process to achieve maximum customer satisfaction at the lowest overall cost to the organization while continuing to improve the process.
project management
The application of knowledge, skills, tools, and techniques to a broad range of activities to meet the requirements of a particular project.
statistical process control (SPC)
The application of statistical techniques to control a process; often used interchangeably with the term statistical quality control. A tool that controls and monitors the process, to ensure that it is operating at its potential.
corrective action recommendation (CAR)
The full cycle corrective action tool that offers ease and simplicity for employee involvement in the corrective action/process improvement cycle.
prevention costs
costs associated with preventing defects before they happen
internal failure costs
costs resulting from defects that are discovered during the production of a service or product
external failure costs
costs that arise when a defect is discovered after the customer receives the service or product
probability
likelihood that a particular event will occur; between 0 and 1
replication
repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances
dispersion
sample data is quantified with standard deviation and mean
system
A group of interdependent processes and people that together perform a common mission.
charter
A written commitment approved by management stating the scope of authority for an improvement project or team.
inspection, 100 percent
Inspection of all the units in the lot or batch.
inspection, normal
Inspection used in accordance with a sampling plan under ordinary circumstances.
Traceability
The accuracy of a measuring instrument mapped to US national standard
validation
The act of confirming that a product or service meets the requirements for which it was intended.
verification
The act of determining whether products and services conform to specific requirements.
measurement
The act or process of quantitatively comparing results with requirements.
enumerative (descriptive) studies
A group of methods used for organizing, summarizing, and representing data using tables, graphs, and summary statistics.1
key process characteristic
A process parameter that can affect safety or compliance with regulations, fit, function, performance, or subsequent processing of product.
key product characteristic
A product characteristic that can affect safety or compliance with regulations, fit, function, performance, or subsequent processing of product.
internal failure
A product failure that occurs before the product is delivered to external customers.
chain reaction
A chain of events described by W. Edwards Deming: improve quality, decrease costs, improve productivity, increase market share with better quality and lower price, stay in business, provide jobs, and provide more jobs.
variation
A change in data, characteristic, or function caused by one of four factors: special causes, common causes, tampering, or structural variation.
experimental factor
A car assembly plant sets the number of employees that could work on one car at the same time, as four. Example
random cause
A cause of variation due to chance and not assignable to any factor.
production part approval process (PPAP)
A "Big Three" automotive process that defines the generic requirements for approval of production parts, including production and bulk materials. Its purpose is to determine during an actual production run at the quoted production rates whether all customer engineering design record and specification requirements are properly understood by the supplier and that the process has the potential to produce product consistently meeting these requirements.
kanban
A Japanese term for one of the primary tools of a just-in-time system. It maintains an orderly and efficient flow of materials throughout the entire manufacturing process. It is usually a printed card that contains specific information such as part name, description, and quantity. Kanban Analysis is used as a materials planning requirement technique, used to identify bottlenecks.
kaizen
A Japanese term that means gradual unending improvement by doing little things better and setting and achieving increasingly higher standards. Masaaki Imai made the term famous in his book Kaizen: The Key to Japan's Competitive Success.
TRIZ
A Russian acronym for a theory of innovative problem solving. TRIZ plays is important in the design phase. It is in this phase of creation, through breaking down barriers of novel thinking, that new products or processes that cannot be had with the current technologies, could be designed.
analysis of variance (ANOVA)
A basic statistical technique for determining the proportion of influence a factor or set of factors has on total variation. It subdivides the total variation of a data set into meaningful component parts associated with specific sources of variation to test a hypothesis on the parameters of the model or to estimate variance components. There are three models: fixed, random, and mixed. Alternative hypothesis is valid for one way Anova is at least one of the group means is different.
design of experiments (DOE)
A branch of applied statistics dealing with planning, conducting, analyzing, and interpreting controlled tests to evaluate the factors that control the value of a parameter or group of parameters. 568 Glossary
champion
A business leader or senior manager who ensures that resources are available for training and projects, and who is involved in periodic project reviews; also an executive who supports and addresses Six Sigma organizational issues.
critical to quality (CTQ)
A characteristic of a product or service that is essential to ensure customer satisfaction.2 cumulative sum control chart (CUSUM)—A control chart on which the plotted value is the cumulative sum of deviations of successive samples from a target value. The ordinate of each plotted point represents the algebraic sum of the previous ordinate and the most recent deviations from the target.
run chart
A chart showing a line connecting numerous data points collected from a process running over time.
control chart
A chart with upper and lower control limits on which values of some statistical measure for a series of samples or subgroups are plotted. The chart frequently shows a central line to help detect a trend of plotted values toward either control limit.
inspection lot
A collection of similar units or a specific quantity of similar material offered for inspection and acceptance at one time.
random sampling
A commonly used sampling technique in which sample units are selected so all combinations of n units under consideration have an equal chance of being selected as the sample.
standard deviation (statistical)
A computed measure of variability indicating the spread of the data set around the mean.
Student's t-distribution
A continuous distribution of the ratio of two independent random variables—a standard normal and a chi-square.1
F-distribution
A continuous probability distribution of the ratio of two independent chi-square random variables.1
demerit chart
A control chart for evaluating a process in terms of a demerit (or quality score); in other words, a weighted sum of counts of various classified nonconformities.
count per unit chart
A control chart for evaluating the stability of a process in terms of the average count of events of a given classification per unit occurring in a sample.
count chart
A control chart for evaluating the stability of a process in terms of the count of events of a given classification occurring in a sample; known as a "c-chart."
multivariate control chart
A control chart for evaluating the stability of a process in terms of the levels of two or more variables or characteristics.
percent chart
A control chart for evaluating the stability of a process in terms of the percentage of the total number of units in a sample in which an event of a given classification occurs. Also referred to as a proportion chart.
average chart
A control chart in which the subgroup average, x -, is used to evaluate the stability of the process level.
range chart (R chart)
A control chart in which the subgroup range R evaluates the stability of the variability within a process, indicates gains or losses in uniformity.
sample standard deviation chart (s-chart)
A control chart in which the subgroup standard deviation s is used to evaluate the stability of the variability within a process.
DMADV
A data-driven quality strategy for designing products and processes; it is an integral part of a Six Sigma quality initiative. It consists of five interconnected phases: define, measure, analyze, design, and verify. "Doing it right the first time"- used when process is available but not capable
DMAIC
A data-driven quality strategy for improving processes, and an integral part of a Six Sigma quality initiative. DMAIC is an acronym for define, measure, analyze, improve, and control.
defective
A defective unit; a unit of product that contains one or more defects with respect to the quality characteristic(s) under consideration. Also known as a nonconformance
lot
A defined quantity of product accumulated under conditions considered uniform for sampling purposes.
lot, batch
A definite quantity of some product manufactured under conditions of production that are considered uniform.
process flow diagram
A depiction of the flow of materials through a process, including any rework or repair operations; also called a process flow chart.
activity network diagram
A diagram that links tasks with direct arrows showing the path through the task list. Tasks are linked when a task is dependent on a preceding task. (AKA arrow diagram.) Included with parallel activity paths
block diagram
A diagram that shows the operation, interrelationships, and interdependencies of components in a system. Boxes, or blocks (hence the name), represent the components; connecting lines between the blocks represent interfaces. There are two types of block diagrams: a functional block diagram, which shows a system's subsystems and lower-level products and their interrelationships and which interfaces with other systems; and a reliability block diagram, which is similar to the functional block diagram but is modified to emphasize those aspects influencing reliability.
venn diagram
A diagram that uses circles to display elements of different sets. Overlapping circles show common elements, called unions. Rectangle in diagram is called a universe.
binomial distribution
A discrete distribution that is applicable whenever an experiment consists of n independent Bernoulli trials and the probability of an outcome, say, success, is constant throughout the experiment.1
Poisson distribution
A discrete probability distribution that expresses the probability of a number of events occurring in a fixed time period if these events occur with a known average rate and are independent of the time since the last event.
specification
A document that states the requirements to which a given product or service must conform.
breakthrough improvement
A dynamic, decisive movement to a new, higher level of performance.
root cause
A factor that caused a nonconformance and should be permanently eliminated through process improvement.
experimental design
A formal plan that details the specifics for conducting an experiment, such as which responses, factors, levels, blocks, treatments, and tools are to be used.
quality management system (QMS)
A formalized system that documents the structure, responsibilities, and procedures required to achieve effective quality management.
Bayes's theorem
A formula to calculate conditional probabilities by relating the conditional and marginal probability distributions of random variables.
plan-do-check-act (PDCA) cycle
A four-step process for quality improvement. In the first step (plan), a way to effect improvement is developed. In the second step (do), the plan is carried out, preferably on a small scale. In the third step (check), a study takes place comparing what was predicted and what was observed in the previous step. In the last step (act), action is taken on the causal system to effect the desired change. The plan-do-check-act cycle is sometimes referred to as the Shewhart cycle, because Walter A. Shewhart discussed the concept in his book Statistical Method from the Viewpoint of Quality Control, and as the Deming cycle, because W. Edwards Deming introduced the concept in Japan. The Japanese subsequently called it the Deming cycle. Also called the plan-do-study-act (PDSA) cycle.
Automotive Industry Action Group (AIAG)
A global automotive trade association with about 1600 member companies that focuses on common business processes, implementation guidelines, education, and training.
American Society for Quality (ASQ)
A global community of people dedicated to quality who share the ideas and tools that make our world work better. With individual and organizational members around the world, ASQ has the reputation and reach to bring together the diverse quality champions who are transforming the world's corporations, organizations, and communities to meet tomorrow's critical challenges.
operating characteristic curve (OC curve)
A graph to determine the probability of accepting lots as a function of the lots' or processes' quality level when using various sampling plans. There are three types: type A curves, which give the probability of acceptance for an individual lot coming from finite production (will not continue in the future); type B curves, which give the probability of acceptance for lots coming from a continuous process; and type C curves, which (for a continuous sampling plan) give the long-run percentage of product accepted during the sampling phase.
histogram
A graphic summary of variation in a set of data. The pictorial nature of a histogram lets people see patterns that are difficult to detect in a simple table of numbers. One of the "seven tools of quality." Expected to reveal Whether or not the data are normally distributed, Customer expectations. A histogram reflects the voice of the process.
flowchart
A graphical representation of the steps in a process. Flowcharts are drawn to better understand processes. One of the "seven tools of quality." PDPC charts, tree diagrams, activity network diagrams, cause and effect, use flowcharting.
scatter diagram
A graphical technique to analyze the relationship between two variables. Two sets of data are plotted on a graph, with the y-axis being used for the variable to be predicted and the x-axis being used for the variable to make the prediction. The graph will show possible relationships (although two variables might appear to be related, they might not be; those who know most about the variables must make that evaluation). One of the "seven tools of quality." Used in Analysis Phase with Linear Regression models.
Pareto chart
A graphical tool for ranking causes from most significant to least significant. It is based on the Pareto principle, which was first defined by Joseph M. Juran in 1950. The principle, named after 19th-century economist Vilfredo Pareto, suggests that most effects come from relatively few causes; that is, 80 percent of the effects come from 20 percent of the possible causes. One of the "seven tools of quality." Cumulative frequency distribution is required for Pareto Analysis
team
A group of individuals organized to work together to accomplish a specific objective. Also see stages of team growth.
error detection
A hybrid form of error-proofing. It means a bad part can be made but will be caught immediately, and corrective action will be taken to prevent another bad part from being produced. A device is used to detect and stop the process when a bad part is made. This is used when error-proofing is too expensive or not easily implemented.
theory of constraints (TOC)
A lean management philosophy that stresses removal of constraints to increase throughput while decreasing inventory and operating expenses. TOC's set of tools examines the entire system for continuous improvement. The current reality tree, conflict resolution diagram, future reality tree, prerequisite tree, and transition tree are the five tools used in TOC's ongoing improvement process. Also called constraints management. Internal constraints consist of Policy, Equipment, People.
standard work instructions
A lean manufacturing tool that enables operators to observe a production process with an understanding of how assembly tasks are to be performed. It ensures that the quality level is understood and serves as an excellent training aid, enabling replacement or temporary individuals to easily adapt and perform the assembly operation.
centerline
A line on a graph that represents the overall average (mean) operating level of the process.
balanced scorecard
A management system that provides feedback on both internal business processes and external outcomes to continuously improve strategic performance and results. Four dimensions are: Financial, Customer, Internal process and Innovation
affinity diagram
A management tool for organizing information (usually gathered during a brainstorming activity) into categories. To group ideas for a new or potentially complex problem, a team would most likely employ:
interrelationship diagram
A management tool that depicts the relationship among factors in a complex situation; also called a relations diagram.
lean enterprise
A manufacturing company organized to eliminate all unproductive effort and unnecessary investment, both on the shop floor and in office functions.
decision matrix
A matrix teams use to evaluate problems or possible solutions. For example, a team might draw a matrix to evaluate possible solutions, listing them in the far left vertical column. Next, the team selects criteria to rate the possible solutions, writing them across the top row. Then, each possible solution is rated on a scale of 1 to 5 for each criterion, and the rating is recorded in the corresponding grid. Finally, the ratings of all the criteria for each possible solution are added to determine its total score. The total score is then used to help decide which solution deserves the most attention.
mean
A measure of central tendency; the arithmetic average of all measurements in a data set.
correlation (statistical)
A measure of the relationship between two data sets of variables. the sign of the r value represents if r is positive, the slope of the line is increasing.
continuous flow production
A method in which items are produced and moved from one processing step to the next, one piece at a time. Each process makes only the one piece that the next process needs, and the transfer batch size is one. Also referred to as one-piece flow and single-piece flow. Glossary 565
heijunka
A method of leveling production, usually at the final assembly line, that makes just-in-time production possible. It involves averaging both the volume and sequence of different model types on a mixed-model production line. Using this method avoids excessive batching of different types of product and volume fluctuations in the same product.
parts per million (ppm)
A method of stating the performance of a process in terms of actual nonconforming material, which can include rejected, returned, or suspect material in the calculation.
Six Sigma
A method that provides organizations tools to improve the capability of their business processes. This increase in performance and decrease in process variation lead to defect reduction and improvement in profits, employee morale, and quality of products or services. Six Sigma quality is a term generally used to indicate that a process is well controlled (±6s from the centerline in a control chart).
t-test
A method to assess whether the means of two groups are statistically different from each other.
nonlinear parameter estimation
A method whereby the arduous and labor-intensive task of multiparameter model calibration can be carried out automatically under the control of a computer.
MIL-STD-105E
A military standard that describes the sampling procedures and tables for inspection by attributes.
assignable cause
A name for the source of variation in a process that is not due to chance and therefore can be identified and eliminated. Also called "special cause."
International Organization for Standardization
A network of national standards institutes from 157 countries working in partnership with international organizations, governments, industry, business, and consumer representatives to develop and publish international standards; acts as a bridge between public and private sectors.
quality loss function
A parabolic approximation of the quality loss that occurs when a quality characteristic deviates from its target value. The quality loss function is expressed in monetary units: the cost of deviating from the target increases quadratically the farther the quality characteristic moves from the target. The formula used to compute the quality loss function depends on the type of quality characteristic being used. The quality loss function was first introduced in this form by Genichi Taguchi.
value stream mapping
A pencil and paper tool used in two stages. First, follow a product's production path from beginning to end and draw a visual representation of every process in the material and information flows. Second, draw a future state map of how value should flow. The most important map is the future state map. value-added—A term used to describe activities that transform input into a customer (internal or external)-usable output. Changeover time, Number of Shifts, Uptime will be included in data boxes for process steps. It helps an organization drive change to reduce waste and improve customer satisfaction.
zero defects
A performance standard and method Philip B. Crosby developed, which states that if people commit themselves to watching details and avoiding errors, they can move closer to the goal of zero defects.
Sponsor
A person or group who provides resources and support for the project, program, or portfolio and is accountable for enabling success.
external customer
A person or organization that receives a product, service, or information but is not part of the organization supplying it. Also see internal customer.
continuous quality improvement (CQI)
A philosophy and attitude for analyzing capabilities and processes and improving them repeatedly to achieve customer satisfaction.
matrix diagram
A planning tool for displaying the relationships among various data sets.
arrow diagram
A planning tool used to diagram a sequence of events or activities (nodes) and their interconnectivity. It is used for scheduling and especially for determining the critical path through nodes. (AKA activity network diagram.)
standard work
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. All jobs are organized around human motion to create an efficient sequence without waste. Work Glossary 583 organized in such a way is called standard(ized) work. The three elements that make up standard work are takt time, working sequence, and standard in-process stock.
American National Standards Institute (ANSI)
A private, nonprofit organization that administers and coordinates the U.S. voluntary standardization and conformity assessment system. It is the U.S. member body in the International Organization for Standardization, known as ISO.
failure mode analysis (FMA)
A procedure to determine which malfunction symptoms appear immediately before or after a failure of a critical parameter in a system. After all possible causes are listed for each symptom, the product is designed to eliminate the problems. failure mode and effects analysis (FMEA)—A systematized group of activities to recognize and evaluate the potential failure of a product or process and its effects, identify actions that could eliminate or reduce the occurrence of the potential failure, and document the process. DFMEA precedes PFMEA.
changeover
A process in which a production device is assigned to perform a different operation or a machine is set up to make a different part—for example, a new plastic resin and new mold in an injection molding machine. Changeover time consists of the total time taken from last good piece to first good piece after changeover. Analyzes and determines External and internal activities. Internal setup is converted to external setup.
single-piece flow
A process in which products proceed one complete product at a time, through various operations in design, order taking, and production without interruptions, backflows, or scrap.
in-control process
A process in which the statistical measure being evaluated is in a state of statistical control; in other words, the variations among the observed sampling results can be attributed to a constant system of chance causes (common causes). Also see out-of-control process.
out-of-control process
A process in which the statistical measure being evaluated is not in a state of statistical control. In other words, the variations among the observed sampling results can not be attributed to a constant system of chance causes. Also see in-control process.
house of quality
A product planning matrix, somewhat resembling a house, that is developed during quality function deployment and shows the relationship of customer requirements to the means of achieving these requirements. Included in HOQ: Competitor preference, Customer satisfaction, Technical specifications. Ranking is based primarily off customer's perspective.
defect
A product's or service's nonfulfillment of an intended requirement or reasonable expectation for use, including safety considerations. There are four classes of defects: class 1, very serious, leads directly to severe injury or catastrophic economic loss; class 2, serious, leads directly to significant injury or significant economic loss; class 3, major, is related to major problems with respect to intended normal or reasonably foreseeable use; and class 4, minor, is related to minor problems with respect to intended normal or reasonably foreseeable use.
total productive maintenance (TPM)
A series of methods, originally pioneered by Nippondenso (a member of the Toyota group), to ensure that everymachine in a production process is always able to perform its required tasksso production is never interrupted.
data
A set of collected facts. There are two basic kinds of numerical data: measured or variables data, such as "16 ounces," "4 miles," and "0.75 inches," and counted or attributes data, such as "go/no go" or "yes/no."
process
A set of interrelated work activities characterized by a set of specific inputs and value-added tasks that make up a procedure for a set of specific outputs.
geometric dimensioning and tolerancing (GD&T)
A set of rules and standard symbols to define part features and relationships on an engineering drawing depicting the geometric relationship of part features and allowing the maximum tolerance that permits full function of the product.
analytical (inferential) studies
A set of techniques used to arrive at a conclusion about a population based upon the information contained in a sample taken from that population.
check sheet
A simple data recording device. The check sheet is custom-designed by the user, which allows him or her to readily interpret the results. The check sheet is one of the "seven tools of quality."
corrective action
A solution meant to reduce or eliminate an identified problem.
supplier
A source of materials, service, or information input provided to a process.
acceptance sampling plan
A specific plan that indicates the sampling sizes and associated acceptance or nonacceptance criteria to be used. In attributes sampling, for example, there are single, double, multiple, sequential, chain, and skip-lot sampling plans. In variables sampling, there are single, double, and sequential sampling plans. For detailed descriptions of these plans, see the standard ANSI/ISO/ASQ A3534-2-1993: Statistics—Vocabulary and symbols— Statistical quality control.
metric
A standard for measurement, an evaluation method.
key performance indicator (KPI)
A statistical measure of how well an organization is doing in a particular area. A KPI could measure a company's financial performance or how it is holding up against customer requirements.
process capability
A statistical measure of the inherent process variability of a given characteristic. The most widely accepted formula for process capability is six sigma.
analysis of means (ANOM)
A statistical procedure for troubleshooting industrial processes and analyzing the results of experimental designs with factors at fixed levels. It provides a graphical display of data. Ellis R. Ott developed the procedure in 1967 because he observed that nonstatisticians had difficulty understanding analysis of variance. Analysis of means is easier for quality practitioners to use because it is an extension of the control chart. In 1973, Edward G. Schilling further extended the concept, enabling analysis of means to be used with nonnormal distributions and attributes data in which the normal approximation to the binomial distribution does not apply. This is referred to as analysis of means for treatment effects.
regression analysis
A statistical technique for determining the best mathematical expression describing the functional relationship between one response variable and one or more independent variables.
customer relationship management (CRM)
A strategy for learning more about customers' needs and behaviors to develop stronger relationships with them. It brings together information about customers, sales, marketing effectiveness, responsiveness, and market trends. It helps businesses use technology and human resources to gain insight into the behavior of customers and the value of those customers.
quality function deployment (QFD)
A structured method in which customer requirements are translated into appropriate technical requirements for each stage of product development and production. The QFD process is often referred to as listening to the voice of the customer. A planning process for products and services. HOQ is a key component.
quality
A subjective term for which each person or sector has its own definition. In technical usage, quality can have two meanings: 1. the characteristics of a product or service that bear on its ability to satisfy stated or implied needs; 2. a product or service free of deficiencies. According to Joseph M. Juran, quality means "fitness for use"; according to Philip Crosby, it means "conformance to requirements."
quality audit
A systematic, independent examination and review to determine whether quality activities and related results comply with plans and whether these plans are implemented effectively and are suitable to achieve the objectives.
force-field analysis
A technique for analyzing what aids or hinders an organization in reaching an objective. An arrow pointing to an objective is drawn down the middle of a piece of paper. The factors that will aid the objective's achievement, called the driving forces, are listed on the left side of the arrow. The factors that will hinder its achievement, called the restraining forces, are listed on the right side of the arrow.
five whys
A technique for discovering the root causes of a problem and showing the relationship of causes by repeatedly asking the question, "Why?"
benchmarking
A technique in which a company measures its performance against that of best-in-class companies, determines how those companies achieved their performance levels, and uses the information to improve its own performance. Subjects that can be benchmarked include strategies, operations, and processes.
brainstorming
A technique teams use to generate ideas on a particular subject. Each person on the team is asked to think creatively and write down as many ideas as possible. The ideas are not discussed or reviewed until after the brainstorming session. Affinity diagrams and interelationship digraphs would benefit most from brainstorming.
point of use
A technique that ensures people have exactly what they need to do their jobs—work instructions, parts, tools, and equipment—where and when they need them.
nominal group technique (NGT)
A technique, similar to brainstorming, used to generate ideas on a particular subject. Team members are asked to silently write down as many ideas as possible. Each member is then asked to share one idea, which is recorded. After all the ideas are recorded, they are discussed and prioritized by the group. You continue this technique until the exercise becomes impractical.
total quality management (TQM)
A term coined by the Naval Air Systems Command to describe its Japanese-style management approach to quality improvement. Since then, TQM has taken on many meanings. Simply put, it is a management approach to long-term success through customer satisfaction. TQM is based on all members of an organization participating in improving processes, products, services, and the culture in which they work. The methods for implementing this approach are found in the teachings of such quality leaders as Philip B. Crosby, W. Edwards Deming, Armand V. Feigenbaum, Kaoru Ishikawa, and Joseph M. Juran.
efficient
A term describing a process that operates effectively while consuming minimal resources (such as labor and time).
six sigma quality
A term generally used to indicate process capability in terms of process spread measured by standard deviations in a normally distributed process.
eighty-twenty (80-20)
A term referring to the Pareto principle, which was first defined by J. M. Juran in 1950. The principle suggests that most effects come from relatively few causes; that is, 80 percent of the effects come from 20 percent of the possible causes. Also see Pareto chart.
non-value-added
A term that describes a process step or function that is not required for the direct achievement of process output. This step or function is identified and examined for potential elimination. Also see value-added.
out of spec
A term that indicates a unit does not meet a given requirement or specification.
fitness for use
A term used to indicate that a product or service fits the customer's defined purpose for that product or service.
central limit theorem
A theorem that states that irrespective of the shape of the distribution of a population, the distribution of sample means is approximately normal when the sample size is large. 30 samples are considered efficient.
cause-and-effect diagram
A tool for analyzing process dispersion. It is also referred to as the "Ishikawa diagram," because Kaoru Ishikawa developed it, Glossary 563 and the "fishbone diagram," because the completed diagram resembles a fish skeleton. The diagram illustrates the main causes and subcauses leading to an effect (symptom). The cause-and-effect diagram is one of the "seven tools of quality."
checklist
A tool for ensuring that all important steps or actions in an operation have been taken. Checklists contain items important or relevant to an issue or situation. Checklists are often confused with check sheets chi square distribution—Probability distribution of sum of squares of n independent normal variables.1
chart
A tool for organizing, summarizing, and depicting data in graphic form. 564 Glossary
SIPOC diagram
A tool used by Six Sigma process improvement teams to identify all relevant elements (suppliers, inputs, process, outputs, customers) of a process improvement project before work begins. Approximately 5-7 steps in the process.
Gantt chart
A type of bar chart used in process planning and control to display planned and finished work in relation to time.
process map
A type of flowchart depicting the steps in a process and identifying responsibility for each step and key measures. Used for detecting the causes for delays
preventive action
Action taken to remove or improve a process to prevent potential future occurrences of a nonconformance. 578 Glossary
7M tools of Six Sigma
Affinity Diagrams, Tree Diagrams, Interrelationship diagraph, Process Decision Program charts (PDPC), Matrix diagrams, Prioritization matrices and Activity Network diagram.
conformity assessment
All activities concerned with determining that relevant requirements in standards or regulations are fulfilled, including sampling, testing, inspection, certification, management system assessment and registration, accreditation of the competence of those activities, and recognition of an accreditation program's capability.
value stream
All activities, both value-added and non-value-added, required to bring a product from raw material state into the hands of the customer, bring a customer requirement from order to delivery, and bring a design from concept to launch. Also see hoshin planning.
nonparametric tests
All tests involving ranked data (data that can be put in order). Nonparametric tests are often used in place of their parametric counterparts when certain assumptions about the underlying population are questionable. For example, when comparing two independent samples, the Wilcoxon Mann-Whitney test (see entry) does not assume that the difference between the samples is normally distributed, whereas its parametric counterpart, the two-sample t-test, does. Nonparametric tests can be, and often are, more powerful in detecting population differences when certain assumptions are not satisfied. The unpaired T test is an alternative.
first-pass yield (FPY)
Also referred to as the quality rate, the percentage of units that completes a process and meets quality guidelines without being scrapped, rerun, retested, returned, or diverted into an offline repair area. FPY is calculated by dividing the units entering the process minus the defective units by the total number of units entering the process.
Certified Six Sigma Black Belt (CSSBB)
An ASQ certification.
Certified Six Sigma Green Belt (CSSGB)
An ASQ certification.
prioritization matrix
An L-shaped matrix that uses pairwise comparisons of a list of options to a set of criteria in order to choose the best option(s). First, the importance of each criterion is decided. Then, each criterion is considered separately, with each option rated for how well it meets the criterion. Finally, all the ratings are combined for a final ranking of options. Numerical calculations ensure a balance between the relative importance of the criteria and the relative merits of the options.4
activity based costing
An accounting system that assigns costs to a product based on the amount of resources used to design, order, or make it.
critical path method (CPM)
An activity-oriented project management technique that uses arrow-diagramming techniques to demonstrate both the time and the cost required to complete a project. It provides one-time estimate: normal time. The earliest time represents the estimated time at which the event will occur if the preceding activities are started as early as possibleThe latest time for an event is the estimated time the event can occur without delaying the completion of the project beyond its earliest time. Slack time for an event is the difference between the latest and earliest times for a given event, hence incorrect. Budgeted time is not a component of critical path.
conformance
An affirmative indication or judgment that a product or service has met the requirements of a relevant specification, contract, or regulation
pull system
An alternative to scheduling individual processes in which the customer process withdraws the items it needs as at a supermarket, and the supplying process produces to replenish what was withdrawn; used to avoid push. Also see kanban.
Malcolm Baldrige National Quality Award (MBNQA)
An award established by the U.S. Congress in 1987 to raise awareness of quality management and recognize U.S. companies that have implemented successful quality management systems. Awards can be given annually in six categories: manufacturing, service, small business, education, healthcare, and nonprofit. The award is named after the late Secretary of Commerce Malcolm Baldrige, a proponent of quality management. The U.S. Commerce Department's National Institute of Standards and Technology manages the award, and ASQ administers it.
lean manufacturing/production
An initiative focused on eliminating all waste in manufacturing processes. Principles of lean manufacturing include zero waiting time, zero inventory, scheduling (internal customer pull instead of push system), batch to flow (cut batch sizes), line balancing, and cutting actual process times. The production systems are characterized by optimum automation, just-in-time supplier delivery disciplines, quick changeover times, high levels of quality, and continuous improvement.
unit
An object for which a measurement or observation can be made; commonly used in the sense of a "unit of product," the entity of product inspected to determine whether it is defective or nondefective. upper control limit (UCL)—Control limit for points above the central line in a control chart.
just-in-time (JIT) manufacturing
An optimal material requirement planning system for a manufacturing process in which there is little or no manufacturing material inventory on hand at the manufacturing site and little or no incoming inspection. DRIFT stands for Do It Right The First Time
cost of quality (COQ)
Another term for COPQ. It is considered by some to be synonymous with COPQ but is considered by others to be unique. While the two concepts emphasize the same ideas, some disagree as to which concept came first and which categories are included in each.
Deming cycle
Another term for the plan-do-study-act cycle. Walter Shewhart created it (calling it the plan-do-check-act cycle), but W. Edwards Deming popularized it, calling it plan-do-study-act.
waste
Any activity that consumes resources and produces no added value to the product or service a customer receives. Also known as muda.
constraint
Anything that limits a system from achieving higher performance or throughput; also, the bottleneck that most severely limits the organization's ability to achieve higher performance relative to its purpose or goal.
practical significance
At least as important as the question of statistical significance, practical or economic significance determines whether an observed sample difference is large enough to be of practical interest.
x-bar (x-) chart
Average chart.
hoshin planning
Breakthrough planning. A Japanese strategic planning process in which a company develops up to four vision statements that indicate where the company should be in the next five years. Company goals and work plans are developed based on the vision statements. Periodic submitted audits are then conducted to monitor progress. Also see value stream.
first-time quality (FTQ)
Calculation of the percentage of good parts at the beginning of a production run.
common causes
Causes of variation that are inherent in a process over time. They affect every outcome of the process and everyone working in the process. (AKA chance causes.) Also see special causes.
special causes
Causes of variation that arise because of special circumstances. They are not an inherent part of a process. Special causes are also referred to as assignable causes. Also see common causes.
supplier quality assurance
Confidence that a supplier's product or service will fulfill its customers' needs. This confidence is achieved by creating a relationship between the customer and supplier that ensures that the product will be fit for use with minimal corrective action and inspection. According to Joseph M. Juran, nine primary activities are needed: (1) define product and program quality requirements, (2) evaluate alternative suppliers, (3) select suppliers, (4) conduct joint quality planning, (5) cooperate with the supplier during the execution of the contract, (6) obtain proof of conformance to requirements, (7) certify qualified suppliers, (8) conduct quality improvement programs as required, (9) create and use supplier quality ratings.
lower control limit (LCL)
Control limit for points below the central line in a control chart.
appraisal costs
Costs of activities designed to ensure quality or uncover defects
u-chart
Count-per-unit chart. Best for Sample size is variable, Number of defects are investigated, Attribute data.
ordinal data
Data arranged in order. Differences between the values cannot be determined or are meaningless. A ranking scale. Ex. Likert Customer satisfaction scale.The difference between a 2 rating and a 4 rating does not mean the customer is twice as satisfied when giving a 4.
nominal data
Data that consists of names or categories only. Allows us to classify the object.Ex. Is a famous beach or not. Does not allow rankEx. Doesn't rank HOW famous the beach is. Cannot determine the interval. No ordering scheme is possible. Ex. # of M&M colors in a bag.
continuous (variables) data
Data that vary with discontinuity across an interval. The values of continuous data are often represented by floating point numbers. In sampling, continuous data are often referred to as variables data.3
program evaluation and review technique (PERT) charts
Developed during the Nautilus submarine program in the 1950s, a PERT chart resembles an activity network diagram in that it shows task dependencies. It calculates best, average, and worst expected completion times.3
unimodal
Distribution with one clear peak or most frequent value
design record
Engineering requirements, typically contained in various formats; examples include engineering drawings, math data, and referenced specifications.
Cpk index
Equals the lesser of the USL minus the mean divided by three sigma (or the mean) minus the LSL divided by three sigma. The greater the Cpk value, the better.
indicators
Established measures to determine how well an organization is meeting its customers' needs and other operational and financial performance expectations.
paired-comparison tests
Examples are two-mean, equal variance t-test; twomean, unequal variance t-test; paired t-test; and F-test.
process average quality
Expected or average value of process quality.
ratio data
Extension of interval level that includes a zero starting point. Data is high level variable data. There is an inherent zero starting point. Both differences and ratio are meaningful. Classify objects Rank objects Has equal intervals Has a true zero point Ex. Watches that cost $200 and $400. The 2nd one is 2 times as expensive as the first.
five S (5S)
Five Japanese terms beginning with "s" used to create a workplace suited for visual control and lean production. Seiri (sort) means to separate needed tools, parts, and instructions from unneeded materials and to remove the unneeded ones. Seiton (set in order) means to neatly arrange and identify parts and tools for ease of use. Seiso (shine) means to conduct a cleanup campaign. Seiketsu (standardize) means to conduct seiri, seiton, and seiso daily to maintain a workplace in perfect condition. Shitsuke (sustain) means to form the habit of always following the first four S's. Standardize and sustain most difficult to accomplish.
stages of team growth
Four stages that teams move through as they develop maturity: forming, storming, norming, and performing.
factorial design
Fractional Factoria includes at least one trial for some, but not all, possible combination of factors and levels. Full Factorial experiments include at least one trial for each possible combination of factors and levels.
Black Belt (BB)
Full-time team leader responsible for implementing process improvement projects; define, measure, analyze, improve, and control (DMAIC) or define, measure, analyze, design, and verify (DMADV)—within a business to drive up customer satisfaction and productivity levels.
attributes (discrete) data
Go/no-go information. The control charts based on attributes data include percent chart, number of affected units chart, count chart, count per unit chart, quality score chart, and demerit chart.
interval data
Has an interval. Data is arranged in order and differences can be found. No starting point. Ratios are meaningless. Ex. Temperature of 3 pizzas. if one pizza is 100 degrees, that doesn't make a 300 degree object 3 times as hot.
Advanced Product Quality Planning (APQP)
High-level automotive process for product realization, from design through production part approval.
independent
If the occurrence of B has no effect on the occurance of A
mutually exclusive
If two events cannot occur at the same time, they are:
incremental improvement
Improvement implemented on a continual basis.
acceptance quality limit (AQL)
In a continuing series of lots, a quality level that, for the purpose of sampling inspection, is the limit of a satisfactory process average.
chain sampling plan
In acceptance sampling, a plan in which the criteria for acceptance and rejection apply to the cumulative sampling results for the current lot and one or more immediately preceding lots.
continuous sampling plan
In acceptance sampling, a plan, intended for application to a continuous flow of individual units of product, that involves acceptance and rejection on a unit-by-unit basis and employs alternate periods of 100 percent inspection and sampling. The relative amount of 100 percent inspection depends on the quality of submitted product. Continuous sampling plans usually require that each t period of 100 percent inspection be continued until a specified number i of consecutively inspected units is found clear of defects. Note: For single-level continuous sampling plans, a single d sampling rate (for example, inspect one unit in five or one unit in 10) is used during sampling. For multilevel continuous sampling plans, two or more sampling rates can be used. The rate at any given time depends on the quality of submitted product.
sample
In acceptance sampling, one or more units of product (or a quantity of material) drawn from a lot for purposes of inspection to reach a decision regarding acceptance of the lot.
deviation
In numerical data sets, the difference or distance of an individual observation or data value from the center point (often the mean) of the set distribution.
pilot phase
In this phase of implementing an improved process, we may simulate the improvement using mathematical or computer based modeling.
acceptance sampling
Inspection of a sample from a lot to decide whether to accept that lot. There are two types: attributes sampling and variables sampling. In attributes sampling, the presence or absence of a characteristic is noted in each of the units inspected. In variables sampling, the numerical magnitude of a characteristic is measured and recorded for each inspected unit; this involves reference to a continuous scale of some kind.
muda
Japanese for waste; any activity that consumes resources but creates no value for the customer.
poka-yoke
Japanese term that means mistake-proofing. A poka-yoke device is one that prevents incorrect parts from being made or assembled, or easily identifies a flaw or error.
statistical significance
Level of accuracy expected of an analysis of data. Most frequently it is expressed as either a "95 percent level of significance" or "five percent confidence level."5 strengths, weaknesses, opportunities, threats (SWOT) analysis—A strategic technique used to assess an organization's competitive position.
cyclical variation
Looks at the piece-to-piece changes in consecutive order. Patterns are identified in groups, batches, or lots of units.3 Glossary 567
downtime
Lost production time during which a piece of equipment is not operating correctly due to breakdown, maintenance, power failures, or similar events.
project team
Manages the work of a project. The work typically involves balancing competing demands for project scope, time, cost, risk, and quality, satisfying stakeholders with differing needs and expectations, and meeting identified requirements.
data chart
Matrix and prioritization are examples of data charts
kurtosis
Measure of the fatness of the tails of a probability distribution relative to that of a normal distribution. Indicates likelihood of extreme outcomes.Skewness related to symmetry.
variables (attributes) data
Measurement information. Control charts based on variables data include average (x -) chart, range (R) chart, and sample standard deviation (s) chart. 586 Glossary
measurement systems analysis
Measurement is the key and essential in six sigma. Measurement System Analysis (MSA) is an experimental and mathematical method of determining how much the variation within the measurement process contributes to overall process variability. There are five parameters to investigate in an MSA; Bias Linearity Stability Repeatability Reproducibility
process control plan
Measurements and specifications. Frequency of reporting and sampling methodology. Input output to a process.
inspection
Measuring, examining, testing, and gauging one or more characteristics of a product or service and comparing the results with specified requirements to determine whether conformity is achieved for each characteristic.
attributes, method of
Method of measuring quality that consists of noting the presence (or absence) of some characteristic (attribute) in each of the units under consideration and counting how many units do (or do not) possess it. Example: go/no-go gauging of a dimension.
external failure
Nonconformance identified by the external customers.
average run length (ARL)
On a control chart, the number of subgroups expected to be inspected before a shift in magnitude takes place.
sigma
One standard deviation in a normally distributed process.
stakeholders
Parties that are affected by planned and potential unplanned changes to a process by a six sigma projects
Dodge-Romig sampling plans
Plans for acceptance sampling developed by Harold F. Dodge and Harry G. Romig. Four sets of tables were published in 1940: single sampling lot tolerance tables, double sampling lot tolerance tables, single sampling average outgoing quality limit tables, and double sampling average outgoing quality limit tables.
Demming Customer Model
Process inputs, controls, outputs are each interdependent. Statistical models can be used to control and guide these inputs. Process feedback can be used to redesign existing systems and make them better.
batch and queue
Producing more than one piece and then moving the pieces to the next operation before they are needed.
lean
Producing the maximum sellable products or services at the lowest operational cost while optimizing inventory levels and eliminating waste. Regularly scheduled rapid improvement events in which the right people come together to find ways to eliminate waste in business processes and implement their solutions very quickly.
outputs
Products, materials, services, or information provided to customers (internal or external), from a process. Measure of productive capacity
Qualitative and Quantitative factors
Qualitative factors contain a number of categories while Quantitative factors can be set to any specific level
standardization
Reduces the number of characteristics of a system.
linearity
Refers to measurements being statistically different from one end of the measurement space to the other. For example, a measurement process may be very capable of measuring small parts but much less accurate measuring large parts, or one end of a long part can be measured more accurately than the other. Component of accuracy.
business process management
SIPOC, KPIV, KPOV Benchmarking Critical to X
Baldrige Award
See Malcolm Baldrige National Quality Award. baseline measurement—The beginning point, based on an evaluation of output over a period of time, used to determine the process parameters prior to any improvement effort; the basis against which change is measured.
Ishikawa diagram
See cause-and-effect diagram.
fishbone diagram
See cause-and-effect diagram.
quality costs
See cost of poor quality.
c-chart
See count chart.
seven wastes
See eight wastes.
relations diagram
See interrelationship diagram.
proportion chart
See percent chart.
p-chart
See percent chart. Glossary 577
Shewhart cycle
See plan-do-check-act cycle.
Master Black Belt (MBB)
Six Sigma or quality expert responsible for strategic implementations in an organization. An MBB is qualified to teach other Six Sigma facilitators the methods, tools, and applications in all functions and levels of the company, and is a resource for using statistical process control in processes.
discrimination
Smallest detectable increment between two measured values- not the same as Accuracy or repeatability. Whenever you are using a gage then there is a least count or minimum value that you can measure with this gauge.
continuous improvement (CI)
Sometimes called continual improvement. The ongoing improvement of products, services, or processes through incremental and breakthrough improvements.
go/no-go
State of a unit or product. Two parameters are possible: go (conforms to specifications) and no-go (does not conform to specifications).
rational subgrouping
Subgrouping wherein the variation is presumed to be only from random causes. Logical method to collect sample for control chart
eight wastes
Taiichi Ohno originally enumerated seven wastes (muda) and later added underutilized people as the eighth waste commonly found in physical production. The eight are (1) overproduction ahead of demand, (2) waiting for the next process, worker, material, or equipment, (3) unnecessary transport of materials (for example, between functional areas of facilities, or to or from a stockroom or warehouse), (4) overprocessing of parts due to poor tool and product design, (5) inventories more than the absolute minimum, (6) unnecessary movement by employees during the course of their work (such as to look Glossary 569 for parts, tools, prints, or help), (7) production of defective parts, (8) underutilization of employees' brainpower, skills, experience, and talents.
norming
Team members learn to cooperate and support one another while establishing patterns of communication and behavior.
nondestructive testing and evaluation (NDT, NDE)
Testing and evaluation methods that do not damage or destroy the product being tested.
Taguchi methods
The American Supplier Institute's trademarked term for the quality engineering methodology developed by Genichi Taguchi. In this 584 Glossary engineering approach to quality control, Taguchi calls for off-line quality control, online quality control, and a system of experimental design to improve quality and reduce costs.
validity
The ability of a feedback instrument to measure what it was intended to measure; also, the degree to which inferences derived from measurements are meaningful.
requirements
The ability of an item to perform a required function under stated conditions for a stated period of time.
quick changeover
The ability to change tooling and fixtures rapidly (usually within minutes) so multiple products can be run on the same machine.
statistical quality control (SQC)
The application of statistical techniques to control quality. Often used interchangeably with the term statistical process control, although statistical quality control includes acceptance sampling, which statistical process control does not.
process improvement
The application of the plan-do-check-act cycle (see entry) to processes to produce positive improvement and better meet the needs and expectations of customers.
precision
The aspect of measurement that addresses repeatability or consistency when an identical item is measured several times.
average sample number (ASN)
The average number of sample units inspected per lot when reaching decisions to accept or reject.
average total inspection (ATI)
The average number of units inspected per lot, including all units in rejected lots. Applicable when the procedure calls for 100 percent inspection of rejected lots.
mean time between failures (MTBF)
The average time interval between failures for repairable product for a defined unit of measure; for example, operating hours, cycles, and miles.
normal distribution (statistical)
The charting of a data set in which most of the data points are concentrated around the average (mean), thus forming a bell-shaped curve.
accuracy
The closeness of agreement between a test result or measurement result and the accepted/true value.2
calibration
The comparison of a measurement instrument or system of unverified accuracy to a measurement instrument or system of known accuracy to detect any variation from the required performance specification. Purpose: Stability of measurement instrument Purpose of the measurement instrument How the environment interacts with the measurement instrument
business process reengineering (BPR)
The concentration on improving business processes to deliver outputs that will achieve results meeting the firm's objectives, priorities, and mission.
Hawthorne effect
The concept that every change results (initially, at least) in increased productivity.
robustness
The condition of a product or process design that remains relatively stable, with a minimum of variation, even though factors that influence operations or usage, such as environment and wear, are constantly changing.
inspection cost
The cost associated with inspecting a product to ensure that it meets the internal or external customer's needs and requirements; an appraisal cost.
prevention cost
The cost incurred by actions taken to prevent a nonconformance from occurring; one element of cost of quality or cost of poor quality.
failure cost
The cost resulting from the occurrence of defects. One element of cost of quality or cost of poor quality.
cost of poor quality (COPQ)
The costs associated with providing poor-quality products or services. There are four categories: internal failure costs (costs associated with defects found before the customer receives the product or service), external failure costs (costs associated with defects found after the customer receives the product or service), appraisal costs (costs incurred to determine the degree of conformance to quality requirements), and prevention costs (costs incurred to keep failure and appraisal costs to a minimum). 566 Glossary
measure
The criteria, metric, or means to which a comparison is made with output. Reproducibility and repeatability happen during this phase
dependability
The degree to which a product is operable and capable of performing its required function at any randomly chosen time during its specified operating time, provided that the product is available at the start of that period. (Nonoperation related influences are not included.) Dependability can be expressed by the following ratio: time available divided by (time available + time required).
jidoka
The deliberate effort to automate a process with a human touch. It means that when a problem occurs on a production line, a worker or machine is able to stop the process and prevent defective goods from being produced.
Stability
The difference in the average of at least 2 set of measurements with a gage over time. Let we measured an object at Time (T1) and then after time (T2) there average value are totally different.
gage repeatability and reproducibility (GR&R)
The evaluation of a gauging instrument's accuracy by determining whether its measurements are repeatable (there is close agreement among a number of consecutive measurements of the output for the same value of the input under the same operating conditions) and reproducible (there is close agreement among repeated measurements of the output for the same value of input made under the same operating conditions over a period of time).
average outgoing quality (AOQ)
The expected average quality level of an outgoing product for a given value of incoming product quality.
voice of the customer
The expressed requirements and expectations of customers relative to products or services, as documented and disseminated to the providing organization's members.
consumer
The external customer to whom a product or service is ultimately delivered; also called end user.
characteristic
The factors, elements, or measures that define and differentiate a process, function, product, service, or other entity.
dissatisfiers
The features or functions a customer expects that either are not present or are present but not adequate; also pertains to employees' expectations.
trend
The graphical representation of a variable's tendency, over time, to increase, decrease, or remain unchanged. trend control chart—A control chart in which the deviation of the subgroup average, x -, from an expected trend in the process level is used to evaluate the stability of a process.
failure
The inability of an item, product, or service to perform required functions on demand due to one or more defects.
bias
The influence in a sample of a factor that causes the data population or process being sampled to appear different from what it actually is, typically in a specific direction.3
lean migration
The journey from traditional manufacturing methods to one in which all forms of waste are systematically eliminated.
probability (statistical)
The likelihood of occurrence of an event, action, or item.
classification of defects
The listing of possible defects of a unit, classified according to their seriousness. Note: Commonly used classifications: class A, class B, class C, class D; or critical, major, minor, and incidental; or critical, major, and minor. Definitions of these classifications require careful preparation and tailoring to the product(s) being sampled to ensure accurate assignment of a defect to the proper classification. A separate acceptance sampling plan is generally applied to each class of defects.
buffer
The location between each operation in a production line that contains in-process parts. Typically a conveyor, roller-rack or CML (continuously-moving-line). Buffer is placed both before and after the governing constraint. Theory of Constraints (TOC)
tolerance
The maximum and minimum limit values a product can have and still meet customer requirements.
average outgoing quality limit (AOQL)
The maximum average outgoing quality over all possible levels of incoming quality for a given acceptance sampling plan and disposal specification.
acceptance number
The maximum number of defects or defectives allowable in a sampling lot for the lot to be acceptable.
range (statistical)
The measure of dispersion in a data set (the difference between the highest and lowest values). Glossary 581
process control
The method for keeping a process within boundaries; the act of minimizing the variation of a process. process decision program charts (PDPC)—A variant of tree diagrams, a PDPC can be used as a simple alternative to FMEA.3
median
The middle number or center value of a set of data in which all the data are arranged in sequence. Glossary 575
control limits
The natural boundaries of a process within specified confidence levels, expressed as the upper control limit (UCL) and the lower control limit (LCL).
Kruskal-Wallis test
The non-parametric equivalent to the one-way ANOVA. unequal group sizes and the data is skewed. Best for ranked data.
nonconformity
The nonfulfillment of a specified requirement.
N
The number of units in a population.
n
The number of units in a sample.
sample size (n)
The number of units in a sample.
audit
The on-site verification activity, such as inspection or examination, of a product, process, or quality system, to ensure compliance to requirements. Glossary 561 An audit can apply to an entire organization or might be specific to a product, function, process, or production step.
process performance management
The overseeing of process instances to ensure their quality and timeliness; can also include proactive and reactive actions to ensure a good result. Glossary 579
process owner
The person who coordinates the various functions and work activities at all levels of a process, has the authority or ability to make changes in the process as required, and manages the entire process cycle to ensure performance effectiveness.
process management
The pertinent techniques and tools applied to a process to implement and improve process effectiveness, hold the gains, and ensure process integrity in fulfilling customer requirements.
reliability
The probability of a product's performing its intended function under stated conditions without failure for a given period of time.
maintainability
The probability that a given maintenance action for an item under given usage conditions can be performed within a stated time interval when the maintenance is performed under stated conditions using stated procedures and resources.
risk priority number (RPN)
The product of the severity, occurrence, and detection values determined in FMEA. The higher the RPN, the more significant the failure mode.
Toyota Production System (TPS)
The production system developed by Toyota Motor Corp. to provide best quality, lowest cost, and shortest lead time through eliminating waste. TPS is based on two pillars: just-in-time and jidoka. TPS is maintained and improved through iterations of standardized work and kaizen.
inputs
The products, services, and material obtained from suppliers to produce the outputs delivered to customers.
flow
The progressive achievement of tasks along the value stream so a product proceeds from design to launch, order to delivery, and raw to finished materials in the hands of the customer with no stoppages, scrap, or backflows.
throughput
The rate at which the system generates money through sales, or the conversion rate of inventory into shipped product. Is the rate of productivity against (against time).
takt time
The rate of customer demand, takt time is calculated by dividing production time by the quantity of product the customer requires in that time. Takt is the heartbeat of a lean manufacturing system. Also see cycle time.
efficiency
The ratio of the output to the total input in a process.
Cp
The ratio of tolerance to six sigma, or the upper specification limit (USL) minus the lower specification limit (LSL) divided by six sigma. It is sometimes referred to as the engineering tolerance divided by the natural tolerance and is only a measure of dispersion. Best for random sampling of data.
internal customer
The recipient (person or department) within an organization of another person's or department's output (product, service, or information).
causation
The relationship between two variables. The changes in variable x cause changes in y. For example, a change in outdoor temperature causes changes in natural gas consumption for heating. If we can change x, we can bring about a change in y.
certification
The result of a person meeting the established criteria set by a certificate granting organization.
effect
The result of an action being taken; the expected or predicted impact when an action is to be taken or is proposed.
customer satisfaction
The result of delivering a product or service that meets customer requirements.
hoshin kanri
The selection of goals, projects to achieve the goals, designation of people and resources for project completion, and establishment of project metrics.
supply chain
The series of suppliers to a given process.
Ppk (minimum process performance index)
The smaller of upper process performance index and lower process performance index.2
compliance
The state of an organization that meets prescribed specifications, contract terms, regulations, or standards.
effectiveness
The state of having produced a decided on or desired effect.
procedure
The steps in a process and how these steps are to be performed for the process to fulfill a customer's requirements; usually documented.
central tendency
The tendency of data gathered from a process to cluster toward a middle value somewhere between the high and low values of measurement.
queue time
The time a product spends in a line awaiting the next design, order processing, or fabrication step.
cycle time
The time required to complete one cycle of an operation. If cycle time for every operation in a complete process can be reduced to equal takt time, products can be made in single-piece flow. Also see takt time.
changeover time
The time required to modify a system or workstation, usually including both teardown time for the existing condition and setup time for the new condition.
temporal variation
The time-to-time or shift-to-shift variation—that is, variation across time.3
capability
The total range of inherent variation in a stable process determined by using data from control charts.
mode
The value occurring most frequently in a data set.
lot quality
The value of percentage defective or of defects per hundred units in a lot. lot size (also referred to as N)—The number of units in a lot.
process quality
The value of percentage defective or of defects per hundred units in product from a given process. Note: The symbols "p" and "c" are commonly used to represent the true process average in fraction defective or defects per unit, and "l00p" and "100c" the true process average in percentage defective or in defects per hundred units.
process capability index
The value of the inherent tolerance specified for the characteristic divided by the process capability. The several types of process capability indices include the widely used Cpk and Cp.
reproducibility
The variation in measurements made by different people using the same measuring device to measure the same characteristic on the same product. Component of precision with repeatability.
repeatability
The variation in measurements obtained when one measurement device is used several times by the same person to measure the same characteristic on the same product. Component of precision with reproducibility.
Least Squares regression Y = mx + b + e
This equation describes a line with a y axis intercept of b and a slope of m. Least squares regression can be used to identify the coefficients m and b. e is an error term. See linear regression.
Sustain and Improve phase
This phase of implementing an improved process requires the highest level of employee involvement:
seven tools of quality
Tools that help organizations understand their processes to improve them. The tools are the cause-and-effect diagram, check sheet, control chart, flowchart, histogram, Pareto chart, and scatter diagram.
quality assurance/quality control (QA/QC)
Two terms that have many interpretations because of the multiple definitions for the words "assurance" and "control." For example, "assurance" can mean the act of giving confidence, the state of being certain, or the act of making certain; "control" can mean an evaluation to indicate needed corrective responses, the act of guiding, or the state of a process in which the variability is attributable to a constant system of chance causes. (For a detailed discussion on the multiple definitions, see ANSI/ISO/ASQ A3534-2, Statistics Vocabulary and symbols Statistical quality 580 Glossary control.) One definition of quality assurance is: all the planned and systematic activities implemented within the quality system that can be demonstrated to provide confidence that a product or service will fulfill requirements for quality. One definition for quality control is: the operational techniques and activities used to fulfill requirements for quality. Often, however, "quality assurance" and "quality control" are used interchangeably, referring to the actions performed to ensure the quality of a product, service, or process.
positional variation
Type of variation frequently within-piece, but can also include machine-to-machine variation, line-to-line or plant-to-plant variation, within-batch variation, and test positioning variation.3
multivoting
Typically used after brainstorming, multivoting narrows a large list of possibilities to a smaller list of the top priorities (or to a final selection) by allowing items to be ranked in importance by participants. Multivoting is preferable to straight voting because it allows an item that is favored by all, but not the top choice of any, to rise to the top.4
first in, first out (FIFO)
Use of material produced by one process in the same order by the next process. A FIFO queue is filled by the supplying process and emptied by the customer process. When a FIFO lane gets full, production is stopped until the next (internal) customer has used some of that inventory.
error-proofing
Use of process or design features to prevent the acceptance or further processing of nonconforming products. Also known as mistake-proofing.
mistake-proofing
Use of production or design features to prevent the manufacture or passing downstream of a nonconforming product; also known as error-proofing.
design for Six Sigma (DFSS)
Used for developing a new product or process, or for processes that need total overhaul. A process often used in DFSS is called DMADV: define, measure, analyze, design, verify. Considered the 'future of Six Sigma'. Phases that exist in DFSS are DMADV, IDDOV, DMADOV.
Wilcoxon Mann-Whitney test
Used to test the null hypothesis that two populations have identical distribution functions against the alternative hypothesis that the two distribution functions differ only with respect to location (median), if at all. It does not require the assumption that the differences between the two samples are normally distributed. In many applications, it is used in place of the two-sample t-test when the normality assumption is questionable. This test can also be applied when the observations in a sample of data are ranks, that is, ordinal data, rather than direct measurements. Used to evaluate the significant difference between the mean ranks of two groups and used to determine whether the two independent groups are drawn from the same population. Used to investigate whether two independent samples were selected from populations having the same distribution. Considers the position of each observation relative to the overall median
Cpm
Used when a target value within the specification limits is more significant than overall centering.3
risk management
Using managerial resources to integrate risk identification, risk assessment, risk prioritization, development of risk handling strategies, and mitigation of risk to acceptable levels.
Xmr chart
When you have continuous data. When you have subgroups of size = 1.You use the ImR (XmR) chart only when logistical reasons prevent you from having larger subgroups or when there is no reasonable basis for rational subgroups. Particularly useful when you are only making one observations per time period.
operations
Work or steps to transform raw materials to finished product.
control plan (CP)
Written description of the systems for controlling part and process quality by addressing the key characteristics and engineering requirements. It includes: KPIV & KPOV. LSL & USL. Unit of measurement. According to Forrest W. Breyfogle III, said consider at least 7 attributes when creating
statistical process control
a system in which management collects and analyzes information about the production process to pinpoint quality problems in the production system; Early detection of problems,Making statistically valid decisions, Better understand product and process. Used to identify whether the process is moving out of the customer specification zone
tree diagram
are organized by levels of importance, from the whys to the hows or from the goals to the means. A management tool that depicts the hierarchy of tasks and subtasks needed to complete an objective. The finished diagram bears a resemblance to a tree.
parametric tests
are used only where a normal distribution is assumed. The most widely used tests are the t-test (paired or unpaired), ANOVA (one-way non-repeated, repeated; two-way, three-way), linear regression and Pearson rank correlation. Parametric tests are to be performed for normally distributed data. Normal distribution is a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean.
Taguchi's Rule for Manufacturing
includes tolerance design, parameter design and system design.
Walsh Test
is a nonparametric test randomization test for matched pairs. The data type for
Friedman test
is the non-parametric alternative to the one-way ANOVA with repeated measures. It is used to test for differences between groups when the dependent variable being measured is ordinal.
Chi-square test
to test a population variance against a known or assumed value of the population variance. There are basically two types of Chi squares test, Chi-square Test of Independence: Determines is there any association between two categorical variables. Chi-square test for goodness of fit: It is a statistical hypothesis test to see how well sample data fit into population characteristics.
alias structures
used in fractional factorial designs to determine which combinations of factors and levels to be tested
spaghetti diagram
visually illustrates the physical flow of materials. analyzing detailed flow chart is suitable for identifying physical inefficiencies
