Software Testing Experience

Quality Definitions:

acceptable quality level (AQL): 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.

acceptance sampling: inspection of a sample from a lot to decide whether to accept or not 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.

acceptance sampling plan: a specific plan that indicates the sampling sizes and the 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, Statistics – Vocabulary and Symbols – Statistical Quality Control.)

accreditation: certification by a duly recognized body of the facilities, capability, objectivity, competence, and integrity of an agency, service, or operational group or individual to provide the specific service or operation needed. For example, the Registrar Accreditation Board accredits those organizations that register companies to the ISO 9000 series standards.

ACSI: The American Customer Satisfaction Index, released for the first time in October 1994, is a new economic indicator, a cross-industry measure of the satisfaction of U.S. household customers with the quality of the goods and services available to them – both those goods and services produced within the United States and those provided as imports from foreign firms that have substantial market shares or dollar sales. The ACSI is co-sponsored by the University of Michigan Business School and ASQ.

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 where the normal approximation to the binomial distribution does not apply. This is referred to as analysis of means for treatment effects.

analysis of variance (ANOVA): 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.

ANSI: American National Standards Institute

AOQ: average outgoing quality

AOQL: average outgoing quality limit

AQL: acceptable quality level

AQP: Association for Quality and Participation

ASME: American Society of Mechanical Engineers

ASQ: American Society of Quality

ASTD: American Society for Training and Development

ASTM: American Society for Testing and Materials

attribute data: go/no-go information. The control charts based on attribute data include percent chart, number of affected units chart, count chart, count-per-unit chart, quality score chart, and demerit chart.

availability: the ability of a product to be in a state to perform its designated function under stated conditions at a given time. Availability can be expressed by the ratio: uptime divided by (uptime + downtime) being when the product is operative (in active use and in standby state) and downtime being when the product is inoperative time (while under repair, awaiting spare parts, and so on).

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

average outgoing quality (AOQ): the expected average quality level of outgoing product for a given value of incoming product quality.

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.

benchmarking: an improvement process 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. The subjects that can be benchmarked include strategies, operations, processes, and procedures.

big Q, little Q: a term used to contrast the difference between managing for quality in all business processes and products (big Q) and managing for quality in a limited capacity – traditionally in only factory products and processes (little q).

blemish: an imperfection that is severe enough to be noticed but should not cause any real impairment with respect to intended normal or reasonably foreseeable use. See also "defect," "imperfection," and "nonconformity."

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, their interrelationships, and interfaces with other systems; and a reliability block diagram, which is similar to the functional block diagram except that it is modified to emphasize those aspects influencing reliability.

brainstorming: a technique that teams use to generate ideas on a particular subject. Each person in 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.

Brumbaugh, Martin A. (deceased): the founder and first editor of Industrial Quality Control magazine. A former professor of statistics at the University of Buffalo, Brumbaugh's writings on applied statistics were regularly published. Brumbaugh was instrumental in getting two separate quality organizations – the Federated Societies and the Society for Quality Control – merged into one national organization: ASQ. Brumbaugh is an ASQ Honorary member.

BSI: British Standards Institute

c chart: count chart.

CAD: computer-aided design.

CAD/CAM: computer-aided design/computer-assisted manufacturing.

CADRIS: Computer-Aided Design and Reuse with intelligent Support.

calibration: the comparison of a measurement instrument or system of unverified accuracy to a measurement instrument or system of a known accuracy to detect any variation from the required performance specification.

CARM: CMM (capability maturity model) Rating Method.

CART: CMM (capability maturity model) Application Rating Team.

cause-and-effect diagram: a tool for analyzing process dispersion. It is also referred to as the Ishikawa diagram, because Kaoru Ishikawa developed it, and the fishbone diagram, because the complete 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.

CBA: CMM-Based Appraisal.

CBA: CMM-Based Appraisal.

CBA IPI: CMM-based appraisal internal process improvement.

CBA SCE: CBA software capability evaluation CBA IPI. Cabability Maturity Model-based appraisal for internal process improvement.

CER: Cost Estimating Relationship.

CES: Cost Element Structure.

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. Check sheets are often confused with data sheets and checklists (see individual entries).

checklist: a tool used to ensure that all important steps or actions in an operation have been taken. Checklists contain items that are important or relevant to an issue or situation. Checklists are often confused with check sheets and data sheets (see individual entries).

CI: Configuration Item.

CM: configuration management.

CMI: certified mechanical inspector.

CMM: coordinate measurement machine. Usually an automated machine tool that checks for dimensional characteristics of a part or assembly.

CMM: capability maturity model . Developed by the Software Engineering Institute (SEI). The purpose of Capability Maturity Model (CMM®) IntegrationSM is to provide guidance for improving your organization's processes and your ability to manage the development, acquisition, and maintenance of products and services.

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 (see also "special causes").

company culture: a system of values, beliefs, and behaviors inherent in a company. To optimize business performance, top management must define and create the necessary culture.

concurrent engineering: a process in which an organization designs a product or service using input and evaluations from business units and functions early in the process, anticipating problems, and balancing the needs of all parties. The emphasis is on upstream prevention vs. downstream correction.

conformance: an affirmative indication or judgment that a product or service has met the requirements of a relevant specification, contract, or regulation.

continuous improvement: the ongoing improvement of products, services, or processes through incremental and breakthrough improvements.

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.

COPE: Customer-Oriented Provider-Efficient.

corrective action: the implementation of solutions resulting in the reduction or elimination of an identified problem.

cost of poor quality: the costs associated with providing poor-quality products or services. There are four categories of costs: 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).

cost of quality (COQ): a term coined by Philip Crosby referring to the cost of poor quality.

COTS: commercial off-the-shelf.

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.

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.

C_p: a widely used process capability index. It is expressed as C_p = (upper control limit - lower control limit) divided by 6

C_pk: a widely used process capability index. It is expressed as
C_pk = the lesser of USL - divided by 3 or - USL divided by 3

CQA: certified quality auditor.

CQE: certified quality engineer.

CQI: continuous quality improvement.

CQM: certified quality manager.

CQT: certified quality technician.

CRE: certified reliability engineer.

CSQE: certified software quality engineer.

Crosby, Philip: the founder and chairman of the board of Career IV, an executive management consulting firm. Crosby also founded Philip Crosby Associates, Inc. and the Quality College.

cross pilot: see "scatter diagram"

CSCI: computer software configuration item.

cumulative sum control chart: 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.

customer: see "external customer" and "internal customer"

customer delight: the result of delivering a product or service that exceeds customer expectations.

customer satisfaction: the result of delivering a product or service that meets customer requirements.

customer supplier partnership: a long-term relationship between a buyer and supplier characterized by teamwork and mutual confidence. The supplier is considered an extension of the buyer's organization. The partnership is based on several commitments. The buyer provides long-term contracts and uses fewer suppliers. The supplier implements quality assurance processes so that incoming inspection can be minimized. The supplier also helps the buyer reduce costs and improve product and process designs.

d chart: demerit chart

decision matrix: a matrix used by teams to evaluate problems or possible solutions. After a matrix is drawn to evaluate possible solutions, for example, the team lists them in the far-left vertical column. Next, the team selects criteria to rate the possible solutions, writing them across the top row. Third, each possible solution is rated on a scale of 1 to 5 for each criterion and the rating 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.

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 (see also "blemish," "imperfection," and "nonconformity").

demerit chart: a control chart for evaluating a process in terms of a demerit (or quality score), i.e., a weighted sum of counts of various classified nonconformities.

Deming Cycle: see "plan-do-check-act cycle"

Deming Prize: award given annually to organizations that, according to the award guidelines, have successfully applied companywide quality control based on statistical quality control and will keep up with it in the future. Although the award is named in honor of W. Edwards Deming, its criteria are not specifically related to Deming's teachings. There are three separate divisions for the award: the Deming Application Prize, the Deming Prize for Individuals, and the Deming Prize for Overseas Companies. The award process is overseen by the Deming Prize Committee of the Union of Japanese Scientists and Engineers in Tokyo.

Deming, W. Edwards (deceased): a prominent consultant, teacher, and author on the subject of quality. After sharing his expertise in statistical quality control to help the U.S. war effort during World War II, the War Department sent Deming to Japan in 1946 to help that nation recover from its wartime losses. Deming published more than 200 works, including the well-known books Quality, Productivity, and Competitive Position and Out of the Crisis. Deming, who developed the 14 points for managing, is an ASQ Honorary member.

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 ratio: time available divided by (time available + time required)

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.

designing in quality vs. inspecting in quality: see "prevention vs. detection"

diagnostic journey and remedial journey: a two-phase investigation used by teams to solve chronic quality problems. In the first phase, the diagnostic journey, the team journeys from the symptom of a chronic problem to its cause. In the second phase, the remedial journey, the team journeys from the cause to its remedy.

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.

DPMO: Defects Per Million Opportunities.

employee involvement: a practice within an organization whereby employees regularly participate in making decisions on how their work areas operate, including making suggestions for improvement, planning, goal setting, and monitoring performance.

empowerment: a condition whereby employees have the authority to make decisions and take action in their work areas without prior approval. For example, an operator can stop a production process if he detects a problem or a customer service representative can send out a replacement product if a customer calls with a problem.

escape: An undetected nonconformance that reaches the customer.

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.

external customer: a person or organization who receives a product, a service, or information but is not part of the organization supplying it. (See also "internal customer.")

Facilitate: to make easy or easier. Oftern referred to as a facilitator or one who makes meetings more efficient.

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 the possible causes are listed for each symptom, the product is designed to eliminate the problems.

failure mode effects analysis (FMEA): a procedure in which each potential failure mode in every sub-item of an item is analyzed to determine its effect on other sub-items and on the required function of the item.

failure mode effects and criticality analysis (FMECA): a procedure that is performed after a failure mode effects analysis to classify each potential failure effect according to its severity and probability of occurrence

Feigenbaum, Armand V.: the founder and president of General Systems Co., an international engineering company that designs and implements total quality systems. Feigenbaum originated the concept of total quality control in his book, Total Quality Control, which was published in 1951. The book has been translated into many languages, including Japanese, Chinese, French, and Spanish. Feigenbaum is an ASQ Honorary member and served as ASQ president for two consecutive terms.

fishbone diagram: see "cause-and-effect diagram"

fitness for use: a term used to indicate that a product or service fits the customer's defined purpose for that product or service.

flowchart: a graphical representation of the steps in a process. Flowcharts are drawn to better understand processes. The flowchart is one of the seven tools of quality.

FMA: failure mode analysis

FMEA: failure mode effects analysis

FMECA: failure mode effects and criticality analysis

force field analysis: a technique for analyzing the forces that aid or hinder 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.

14 points: W. Edward Deming's 14 management practices to help companies increase their quality and productivity: 1) create constancy of purpose for improving products and services, 2) adopt the new philosophy, 3) cease dependence on inspection to achieve quality, 4) end the practice of awarding business on price alone; instead, minimize total cost by working with a single supplier, 5) improve constantly and forever every process for planning, production, and service, 6) institute training on the job, 7) adopt and institute leadership, 8) drive out fear, 9) break down barriers between staff areas, 10) eliminate slogans, exhortations, and targets for the work force, 11) eliminate numerical quotas for the work force and numerical goals for management, 12) remove barriers that rob people of pride of workmanship and eliminate the annual rating or merit system, 13) institute a vigorous program of education and self-improvement for everyone and, 14) put everybody in the company to work to accomplish the transformation.

funnel experiment: an experiment that demonstrates the effects of tampering. Marbles are dropped through a funnel in an attempt to hit a flat-surfaced target below. The experiment shows that adjusting a stable process to compensate for an undesirable result or an extraordinarily good result will produce output that is worse than if the process had been left alone.

Gantt chart: a type of bar chart used in process planning and control to display planned work and finished work in relation to time.

gauge repeatability and reproducibility (GR&R): the evaluation of a gauging instrument's accuracy by determining whether the measurements taken with it are repeatable (i.e., 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 (i.e., 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).

geometric dimensioning and tolerancing (GDT): a method to minimize production costs by showing the dimension and tolerancing on a drawing while considering the functions or relationships of part features.

George M. Low Trophy: the trophy presented by NASA to those NASA aerospace industry contractors, subcontractors, and suppliers that consistently maintain and improve the quality of their products and services. The award, which was formerly called the NASA Excellence Award for Quality and Productivity, is given in two categories: small business and large business. George M. Low was the NASA administrator for nearly three decades.

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.

Grant, Eugene L.: professor emeritus of economics engineering at Stanford University and an ASQ Honorary member. Grant was part of a small team of professors assigned during World War II to introduce statistical quality control concepts to improve manufacturing production. He has written many textbooks, including Principles of Engineering Economy and Statistical Quality Control, editions of which he coauthored with W. Grant Ireson and Richard S. Leavenworth

histogram: a graphic summary of variation in a set of data. The pictorial nature of the histogram lets people see patterns that are difficult to see in a simple table of numbers. The histogram is one of the seven tools of quality.

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 audits are then conducted to monitor progress.

IEEE: Institute of Electrical and Electronics Engineers

imperfection: a quality characteristic's departure from its intended level or state without any association to conformance to specification requirements or to the usability of a product or service (see also "blemish," "defect," and "nonconformity").

in-control process: a process in which the statistical measure being evaluated is in a state of statistical control, i.e., the variations among the observed sampling results can be attributed to a constant system of chance causes (see also "out-of-control 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.

instant pudding: a term used to illustrate an obstacle to achieving quality: the supposition that quality and productivity improvement is achieved quickly through an affirmation of faith rather than through sufficient effort and education. W. Edwards Deming used this term, which was initially coined by James Bakken of Ford Motor Co., in his book Out of the Crisis.

internal customer: the recipient, person or department, of another person's or department's output (product, service, or information) within an organization (see also "external customer").

IQA: Institute of Quality Assurance

Ishikawa diagram: see "cause-and-effect diagram"

Ishikawa, Kaoru (deceased): a pioneer in quality control activities in Japan. In 1943, he developed the cause-and-effect diagram. Ishikawa, an ASQ Honorary member, published many works, including What is Total Quality Control?, The Japanese Way, Quality Control Circles at Work, and Guide to Quality Control. He was a member of the quality control research group of the Union of Japanese Scientists and Engineers while also working as an assistant professor at the University of Tokyo.

ISO: International Organization for Standardization

ISO 9000 series standards: a set of five individual but related international standards on quality management and quality assurance developed to help companies effectively document the quality system elements to be implemented to maintain an efficient quality system. The standards, initially published in 1987, are not specific to any particular industry, product, or service. The standards were developed by the International Organization for Standardization (ISO), a specialized international agency for standardization composed of the national standards bodies of 91 countries.

Juran, Joseph M.: the chairman emeritus of the Juran Institute and an ASQ Honorary member. Since 1924, Juran has pursued a varied career in management as an engineer, executive, government administrator, university professor, labor arbitrator, corporate director, and consultant. Specializing in managing for quality, he has authored hundreds of papers and 12 books, including Juran's Quality Control Handbook, Quality Planning and Analysis (with F. M. Gryna), and Juran on Leadership for Quality.

JUSE: Union of Japanese Scientists and Engineers

just-in-time manufacturing (JIT): 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.

kaizen: a Japanese term that means gradual unending improvement by doing little things better and setting and achieving increasingly higher standards. The term was made famous by Masaaki Imai in his book, Kaizen: The Key to Japan's Competitive Success.

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.

lot: a defined quantity of product accumulated under conditions that are considered uniform for sampling purposes.

lower control limit (LCL): control limit for points below the central line in a control chart.

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. Maintainability has two categories: serviceability, the ease of conducting scheduled inspections and servicing, and repairability, the ease of restoring service after a failure.

Malcolm Baldrige National Quality Award (MBNQA): an award established by Congress in 1987 to raise awareness of quality management and to recognize U.S. companies that have implemented successful quality management systems. Two awards may be given annually in each of three categories: manufacturing company, service company, and small business. 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.

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, miles.

Median: Relating to or constituting the middle value in a distribution.

MIL-STD: military standard

MIL-Q-9858A: a military standard that describes quality program requirements.

MIL-STD-105E: a military standard that describes the sampling procedures and tables for inspection by attributes.

MIL-STD-45662A: a military standard that describes the requirements for creating and maintaining a calibration system for measurement and test equipment.

MMPP: Marketing Materials Production Process

Mode: The value or item occurring most frequently in a series of observations or statistical data.

MOG: Marketing Operations Group

multivariate control chart: a control chart for evaluating the stability or a process in terms of the levels of two or more variables or characteristics.

n: sample size (the number of units in a sample)

NDE: nondestructive evaluation (See "nondestructive testing and evaluation.")

NIST: National Institute of Standards and Technology

nominal group technique: a technique similar to brainstorming, used by teams to generate ideas on a particular subject. Team members are asked to silently come up with as many ideas as possible, writing them down. Each member is them asked to share one idea, which is recorded. After all the ideas are recorded, they are discussed and prioritized by the group.

nonconformity: the nonfulfillment of a specified requirement (see also "blemish," "defect," and "imperfection").

nondestructive testing and evaluation (NDT): testing and evaluation methods that do not damage or destroy the product being tested.

NQM: National Quality Month

Null Hypothesis: The term that statisticians often use to indicate the statistical hypothesis being tested.

number of affected units chart (np chart): a control chart for evaluating the stability of a process in terms of the total number of units in a sample in which an event of a given classification occurs.

operating characteristic curve (OCcurve): a graph used to determine the probability of accepting lots as a function of the lots' or processes' quality level when using various sampling plans. Three 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.

OSHA: Occupational Safety and Health Administration.

Ott, Ellis R. (deceased): an educator who devoted his career to providing U.S. industry with statistical quality control professionals. In 1946, Ott became the chairman of the mathematics department at Rutgers University's University College with one condition: that he could also consult on and teach quality control. His influence led the university to establish the Rutgers Statistics Center. Ott, an ASQ Honorary member, developed the analysis of means procedure and published many papers.

out-of-control process: a process in which the statistical measure being evaluated is not in a state of statistical control, i.e., the variations among the observed sampling results can be attributed to a constant system of chance causes (see also "in-control process").

out of spec: a term used to indicate that a unit does not meet a given specification.

p chart: percent chart

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 J. 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% of the effects come from 20% of the possible causes. The Pareto chart is one of the seven tools of quality.

PDCA cycle: plan-do-check-act cycle

PE: professional engineer

percent chart: a control chart for evaluating the stability of a process in terms of the percent of the total number of units in a sample in which an event of a given classification occurs. The percent chart is also referred to as a proportion chart.

plan-do-check-act cycle: a four-step process for quality improvement. In the first step (plan), a plan 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), the effects of the plan are observed. In the last step (act), the results are studied to determine what was learned and what can be predicted. 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.

POG: Publications Operations Group

prevention vs. detection: a term used to contrast two types of quality activities. Prevention refers to those activities designed to prevent nonconformances in products and services. Detection refers to those activities designed to detect nonconformances already in products and services. Another term used to describe this distinction is "designing in quality vs. inspecting in quality."

Process A set of interrelated resources and activities which transform inputs into outputs with the aim of adding value.

process capability: a statistical measure of the inherent process variability for a given characteristic. The most widely accepted formula for process capability is 6.

process capability index: the value of the tolerance specified for the characteristic divided by the process capability. There are several types of process capability indexes, including the widely used C_pk and C_p.

process mapping: the flowcharting of a work process.

product or service liability: the obligation of a company to make restitution for loss related to personal injury, property damage, or other harm caused by its product or service.

Q-Q: quantile-quantile

QA: quality assurance

QC: quality control

Q9000 series: refers to ANSI/ISO/ASQ Q9000 series standards, which is the Americanized version of the 1994 edition of the ISO 9000 series standards. The United States adopted the ISO 9000 series standards as the ANSI/ISO/ASQ Q9000 series.

QEIT: quality engineer in training

QIC: Quality Information Center

QMJ: Quality Management Journal

QP:
Quality Progress

quality: a subjective term for which each person has his or her 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 and 2) a product or service free of deficiencies.

quality assurance/quality control: 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 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.

quality audit: a systematic, independent examination and review to determine whether quality activities and related results comply with planned arrangements and whether these arrangements are implemented effectively and are suitable to achieve the objectives.

quality circles: quality improvement or self-improvement study groups composed of a small number of employees – 10 or fewer – and their supervisor. Quality circles originated in Japan, where they are called quality control circles.

quality control (QC): see "quality assurance/quality control"

quality costs: see "cost of poor quality"

quality engineering: the analysis of a manufacturing system at all stages to maximize the quality of the process itself and the products it produces.

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.

Quality Improvement: The organized creation of beneficial changes in process performance levels.

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.

quality score chart (Q chart): a control chart for evaluating the stability of a process in terms of a quality score. The quality score is the weighted sum of the count of events of various classifications where each classification is assigned a weight.

quality trilogy: a three-pronged approach to managing for quality. The three legs are quality planning (developing the products and processes required to meet customer needs), quality control (meeting product and process goals), and quality improvement (achieving unprecedented levels of performance).

quincunx: a tool that creates frequency distributions. Beads tumble over numerous horizontal rows of pins, which force the beads to the right or left. After a random journey, the beads are drop into vertical slots. After many beads are dropped, a frequency distribution results. In the classroom, quincunxes are often used to simulate a manufacturing process. The quincunx was invented by English scientist Francis Galton in the 1890s.

RAM: reliability/availability/maintainability (see individual entries).

random sampling: a commonly used sampling technique in which sample units are selected in such a manner that all combinations of n units under consideration have an equal chance of being selected as the sample.

range chart (R chart): a control chart in which the subgroup range, R, is used to evaluate the stability of the variability within a process.

red bead experiment: an experiment developed by W. Edwards Deming to illustrate that it is impossible to put employees in rank order of performance for the coming year based on their performance during the past year because performance differences must be attributed to the system, not to employees. Four thousand red and white beads, 20% red, in a jar and six people are needed for the experiment. The participants' goal is to produce white beads, because the customer will not accept red beads. One person begins by stirring the beads and then, blindfolded, selects a sample of 50 beads. That person hands the jar to the next person, who repeats the process, and so on. When everyone has his or her sample, the number of red beads for each is counted. The limits of variation between employees that can be attributed to the system are calculated. Everyone will fall within the calculated limits of variation that could arise from the system. The calculations will show that there is no evidence one person will be a better performer than another in the future. The experiment shows that it would be a waste of management's time to try to find out why, say, John produced four red beads and Jane produced 15; instead, management should improve the system, making it possible for everyone to produce more white beads.

Registrar Accreditation Board (RAB): a board that evaluates the competency and reliability of registrars (organizations that assess and register companies to the appropriate ISO 9000 series standards). The Registrar Accreditation Board, formed in 1989 by ASQ, is governed by a board of directors from industry, academia, and quality management consulting firms.

registration to standards: a process in which an accredited, independent third-party organization conducts an on-site audit of a company's operations against the requirements of the standard to which the company wants to be registered. Upon successful completion of the audit, the company receives a certificate indicating that it has met the standard requirements.

regression analysis: a statistical technique for determining the best mathematical expression describing the functional relationship between one response and one or more independent variables.

reliability: the probability of a product performing its intended function under stated conditions without failure for a given period of time.

right the first time: a term used to convey the concept that it is beneficial and more cost-effective to take the necessary steps up front to ensure a product or service meets its requirements than to provide a product or service that will need rework or not meet customers' needs. In other words, an organization should engage in defect prevention rather than defect detection.

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.

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.

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). The scatter diagram is one of the seven tools of quality.

seven tools of quality: tools that help organizations understand their processes in order to improve them. The tools are the cause-and-effect diagram, check sheet, control chart, flowchart, histogram, Pareto chart, and scatter diagram (see individual entries).

Shewhart cycle: see "plan-do-check-act cycle"

Shewhart, Walter A. (deceased): referred to as the father of statistical quality control because he brought together the discipline of statistics, engineering, and economics. He described the basic principles of this new discipline in his book Economic Control of Quality of Manufactured Product. Shewhart, ASQ's first Honorary member, was best known for creating the control chart. Shewhart worked for Western Electric and AT&T Bell Telephone Laboratories in addition to lecturing and consulting on quality control.

signal-to-noise ratio (S/N ratio): a mathematical equation that indicates the magnitude of an experimental effect above the effect of experimental error due to chance fluctuations.

six-sigma quality: a term used generally to indicate that a process is well-controlled, i.e., ±6 sigma from the centerline in a control chart. The term is usually associated with Motorola, which named one of its key operational initiatives "Six Sigma Quality."

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 (see also "common causes").

specification: a document that states the requirements to which a given product or service must conform.

statistical process control (SPC): the application of statistical techniques to control a process. Often the term "statistical quality control" is used interchangeably with "statistical process control."

statistical quality control (SQC): the application of statistical techniques to control quality. Often the term "statistical process control" is used interchangeably with "statistical quality control," although statistical quality control includes acceptance sampling as well as statistical process control.

structural variation: variation caused by regular, systematic changes in output, such as seasonal patterns and long-term trends.

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 the product will be fit for use with minimal corrective action and inspection. According to J. M. Juran, there are nine primary activities 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, and 9) create and use supplier quality ratings.

Taguchi, Genichi: the executive director of the American Supplier Institute, the director of the Japan Industrial Technology Institute, and an honorary professor at Nanjing Institute of Technology in China. Taguchi is well-known for developing a methodology to improve quality and reduce costs, which, in the United States, is referred to as the Taguchi Methods. He also developed the quality loss function.

Taguchi methods: the American Supplier Institute's trademarked term for the quality engineering methodology developed by Genichi Taguchi. In this engineering approach to quality control, Taguchi calls for off-line quality control, on-line quality control, and a system of experimental design to improve quality and reduce costs.

tampering: action taken to compensate for variation within the control limits of a stable system. Tampering increases rather than decreases variation, as evidenced in the funnel experiment.

Team: "a small number of people with complementary skills who are committed to a common purpose, set of performance goals, and approach for which they hold themselves mutually accountable." (Katzenbach, Jon R. and Douglas K. Smith)

top-management commitment: participation of the highest-level officials in their organization's quality improvement efforts. Their participation includes establishing and serving on a quality committee, establishing quality policies and goals, deploying those goals to lower levels of the organization, providing the resources and training that the lower levels need to achieve the goals, participating in quality improvement teams, reviewing progress organizationwide; recognizing those who have performed well, and revising the current reward system to reflect the importance of achieving the quality goals.

total quality management (TQM): a term initially coined by the Naval Air Systems Command to describe its Japanese-style management approach to quality improvement. Since then, total quality management (TQM) has taken on many meanings. Simply put, TQM is a management approach to long-term success through customer satisfaction. TQM is based on the participation of all members of an organization in improving processes, products, services, and the culture they work in. TQM benefits all organization members and society. 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 J. M. Juran.

trend control chart: a control chart in which the deviation of the subgroup average, X-bar, from an expected trend in the process level is used to evaluate the stability of a process.

type I error: an incorrect decision to reject something (such as a statistical hypothesis or a lot of products) when it is acceptable.

type II error: an incorrect decision to accept something when it is unacceptable.

u chart: count per unit chart

Unbiased Statistic: A statistic is an unbiased estimate of a given parameter when the mean of the sampling distribution of that statistic can be shown to be equal to the parameter being estimated.

upper control limit (UCL): control limit for points above the central line in a control chart.

value-adding process: those activities that transform an input into a customer-usable output. The customer can be internal or external to the organization.

variables data: measurement information. Control charts based on variables data include average (X-bar) chart, range (R) chart, and sample standard deviation (s) chart.

variation: a change in data, a characteristic, or a function that is caused by one of four factors: special causes, common causes, tampering, or structural variation (see individual entries).

vital few, useful many: a term used by J. M. Juran to describe his use of the Pareto principle, which he first defined in 1950. (The principal was used much earlier in economics and inventory control methodologies.) The principle suggests that most effects come from relatively few causes; that is, 80% of the effects come from 20% of the possible causes. The 20% of the possible causes are referred to as the "vital few"; the remaining causes are referred to as the "useful many." When Juran first defined this principle, he referred to the remaining causes as the "trivial many," but realizing that no problems are trivial in quality assurance, he changed it to "useful many."

world-class quality: a term used to indicate a standard of excellence: best of the best.

X-bar chart: average chart

zero defects: a performance standard developed by Philip B. Crosby to address a dual attitude in the workplace: people are willing to accept imperfection in some areas, while, in other areas, they expect the number of defects to be zero. This dual attitude had developed because of the conditioning that people are human and humans make mistakes. However, the zero defects methodology states that, if people commit themselves to watching details and avoiding errors, they can move closer to the goal of zero.

Z Score: A measure of the distance in standard deviations of a sample from the mean.