Glossary
A
acceptance number—The maximum number of defects or defectives allowable in
a sampling lot for the lot to be acceptable.
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.
acceptance sampling—Inspection of a sample from a lot to decide whether to
accept that lot. There are two types: attributes sampling and variables sam-
pling. 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
associated acceptance or nonacceptance criteria to be used. In attributes sam-
pling, 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.
accuracy—The closeness of agreement between a test result or measurement result
and the accepted/true value.2
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.
activity network diagram—A diagram that links tasks with direct arrows show-
ing the path through the task list. Tasks are linked when a task is dependent
on a preceding task.3 (AKA arrow diagram.)
Advanced Product Quality Planning (APQP)—High-level automotive process
for product realization, from design through production part approval.
affinity diagram—A management tool for organizing information (usually gath-
ered during a brainstorming activity).
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American National Standards Institute (ANSI)—A private, nonprofit organiza-
tion 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.
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.
analysis of means (ANOM)—A statistical procedure for troubleshooting indus-
trial 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.
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 param-
eters of the model or to estimate variance components. There are three mod-
els: fixed, random, and mixed.
analytical (inferential) studies—A set of techniques used to arrive at a conclu-
sion about a population based upon the information contained in a sample
taken from that population.1
arrow diagram—A planning tool used to diagram a sequence of events or activities
(nodes) and their interconnectivity. It is used for scheduling and e specially for
determining the critical path through nodes. (AKA activity network diagram.)
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.”
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.
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.
audit—The on-site verification activity, such as inspection or examination, of a
product, process, or quality system, to ensure compliance to requirements.
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An audit can apply to an entire organization or might be specific to a product,
function, process, or production step.
Automotive Industry Action Group (AIAG)—A global automotive trade associ-
ation with about 1600 member companies that focuses on common business
processes, implementation guidelines, education, and training.
average chart—A control chart in which the subgroup average, x–, is used to eval-
uate the stability of the process level.
average outgoing quality (AOQ)—The expected average quality level of an out-
going product for a given value of incoming product quality.
average outgoing quality limit (AOQL)—The maximum average outgoing qual-
ity over all possible levels of incoming quality for a given acceptance sampling
plan and disposal specification.
average run length (ARL)—On a control chart, the number of subgroups expected
to be inspected before a shift in magnitude takes place.
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.
B
balanced scorecard—A management system that provides feedback on both inter-
nal business processes and external outcomes to continuously improve strate-
gic performance and results.
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.
batch and queue—Producing more than one piece and then moving the pieces to
the next operation before they are needed.
Bayes’s theorem—A formula to calculate conditional probabilities by relating the
conditional and marginal probability distributions of random variables.
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, oper-
ations, and processes.
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.