Acceptance Number
In judging the acceptability of a lot or batch, this is the maximum number of nonconformities
allowed within a sample, based on a count of the nonconformities. If the batch passes, that is,
it's amount of nonconformities falls at or below the acceptance number. If a batch does not
pass, this usually indicates there is a problem with the process.

Acceptance Sampling Plan
This is a plan for setting up the acceptable sampling technique that includes criteria setting
sample size, and for accepting and rejecting a component, product, or service based on
samples meeting prescribed quality criteria. Plans may involve single, double, sequential,
chain, multiple, or skip-lot sampling techniques. With variable samples, management may
deploy single, double, and sequential sampling techniques.

Accept / Reject Criteria
This refers to the measurement and decision of whether or not the quality and performance
of a product or service is acceptable. These criteria can be technical specifications (such as
level of size tolerances allowed in parts), contract terms and conditions, or performance of
a process or service. Implied in the term is the idea that all processes, products, and actions should have an assigned level of acceptable performance that one can measure. Consistent
with the understanding that criteria grow out of process capabilities, technicians should measure for acceptability to find out how well a process or item is meeting specification.

Adequacy of Standards
This is a manufacturing term that refers to the ability of a standard to be used for calibrating
the accuracy of a gage or instrument used to measure quality or performance. It is best if
such standards are traceable to the National Bureau of Standards. The term also appears
when dealing with the measurement of processes and procedures.

Affinity Diagramming
This is a technique for organizing a variety of subjective data into categories based on the
intuitive relationships among individual pieces of information. It is often used by groups to
find commonalties among concerns and ideas on any subject from members. In this technique, you organize information into logical groups.

Analysis of Means (ANOM)
This is a statistical technique used when running experiments to identify problems and/or capabilities of an industrial process to deliver an end product with the desirable characteristics.

Analysis of Variance (ANOVA)
This is a method for breaking down and analyzing the total variation in the outputs of any
process, understanding the causes of this variation, and then assessing their significance.
The goal is to come up with a process in which variation in outputs will be minimized.

AOQ
This is an acronym for average outgoing quality. This refers to the maximum percent of
defective products that can go to a customer after inspection is performed by an acceptance-sampling plan. AOQ requires 100 percent inspection if defectives in a batch or lot of products exceed some minimum standard. This helps reassure customers that suppliers will deliver products that will not include more defectives than expected.

Calibration
In quality management, this is a comparison of one measurement system or instrument not verified as accurate to another standard measurement system or instrument with verified accuracy. This is done to identify variations from a required specification for performance.

Capability Process Index (Cp)
This is a technique for making a ratio of the specification width (the range within which an
output is considered to meet specification) in relation to the process's natural distribution for assessing whether the process can regularly meet specifications. Process capability is used
to determine which processes are not capable of meeting specifications, to identify those processes operating suboptimally, and to estimate the output proportion that will not conform
to specifications.

Causal Analysis
This technique concentrates on identifying specific failures or defects, discovering root causes
of those failures, and concluding with recommendations on how to eliminate those defects by implementing solutions that address the appropriate cause.

Continuous Sampling Plan
This is an approach to sampling that is most appropriate for the output of processes that deliver
 a continuous flow of a product. In this plan, a company begins by inspecting 100 percent of the units coming from the process. After a certain number of items that have been inspected with no defects, the plan goes to inspecting only a fraction of items. This continues until the company finds a nonconforming unit. At that point, the plan reverts back to 100 percent inspection following the same pattern.

Control Chart
This is a graph and a statistical process control method used to track the capability and performance of a process over time.

Control Chart Factor
This is a factor based on mathematical probability that facilitates the calculation of control limits
on X-bar and range charts.

Cost of Poor Quality (COPQ)
These are the extra expenses caused by delivering poor quality goods or services to customers. These expenses have two sources: (1) internal failure costs (from defects before customers get the product) and (2) external failure costs (costs after a customer receives the poor product or service). Rework, repairs, lost future business, and warranty payments are all examples of costs associated with poor quality.

Cost of Quality (COQ)
This refers to all costs involved in the prevention of defects, assessments of process performance, and measurement of financial consequences. Cost of quality is the cost justification of quality efforts.

Critical Defect
This is a defect that, based on experience, is considered hazardous to employees or to have the potential to harm or injure end users of a product or process.

Defect
This is (a) any nonconformance from a customer's requirement (b) any attribute of a product or service that fails to meet specifications (c) any state of unfitness for use. Defects are usually cataloged into four types by degree, being very serious, serious, major and minor.

Double sampling
This is an inspection technique in which you inspect a first lot of n1 size, which leads you either to accept or reject it. If you reject it, then you inspect a second sample of a larger lot size n2, which in turn leads to a decision to accept or reject the lot.

Failure Mode Effects Analysis (FMEA)
This is a method for designing in reliability and minimizing the causes of failure in a product. It focuses on analyzing origins of product failure by examining raw materials, components, and assembly processes. The goal is to determine the probability of failure in these items and take preventive action based on this analysis.

Inspection
This includes the acts of measuring, testing, examining, or gaging one or more characteristics of the output of a process and then comparing results to specified requirements. The objective is to determine if the output features conform to the specifications of size, function, appearance, and other characteristics that may be relevant to the product or service.

ISO 9000 Standards
This is a set of quality standards developed in 1987 by the International Organization for Standardization. The three major areas of certification are as follows:

ISO 9001, which covers all the processes of a company from design and development to procurement, production, testing, installation and service.

ISO 9002, which covers everything except design and development

ISO 90003, which covers only inspection and testing.

Mean Time Between Failures (MTBF)
This is a measure of the average time between successive failures in the performance of a
product or piece of equipment. It is one measure of reliability of product performance over time. The longer the mean time between failures, the higher the reliability of the product or machine.

Minimum Acceptable Quality
This is the maximum level of defectives or variants in a specified quantity of products, components, or services that, for purposes of quality sampling, can be considered satisfactory
as the average for the outputs delivered by a process.

Process Quality Audit
This is an analysis, appraisal, and evaluation of process performance against certain standards. The audit includes an evaluation of how operators maintain process quality and make accept/reject decisions about outputs.

Q9000 Series
This is an abbreviation for ANSI/ASQC Q9000-1 series of standards, the U.S. version of ISO 9000 standards, adopted by the American National Standards Institute in 1987. They are quality standards, documentation, and audit procedures for a variety of activities performed primarily by manufacturing organizations.

Quality Control
This term refers to those activities a company and its employees undertake to ensure that organizational processes deliver high-quality products or services.

Random Sampling
This is a standard sampling method by which random samples of units are chosen such that all combinations of these units have an equal chance of being chosen as the sample.

Representative Sampling
This is a process by which samples are pulled from batches or lots of units so as to contain minimum bias between the values of the samples' characteristics and the batch, or lot, as a whole.

Root Cause Analysis
This is a quality tool used for identifying the source of defects or problems, focusing on the original cause of the problem or condition. Root cause analysis involves a variety of techniques that define problems and lead to solutions.

Sample
This refers to a specific number of items of a similar type taken from a population or lot, for the purpose of examination, to determine all members of the population or lot conform to quality requirements or specifications.

Statistical Quality Control
This is a broader term than statistical process control, implying the use of statistical techniques to measure and improve processes and quality.

Taguchi Methods
Named after Genichi Taguchi, a leading Japanese expert on quality improvement, these methods comprise a variety of techniques for evaluating quality and figuring out how to improve it. Taguchi based his methods on the idea that any variation from customer requirements represents a loss to customers and to the company.

Variation
This is an idea that suggests there will always be some difference between any two or more actions within a system and in the outputs of that system.

Zero Defects
This is way of explaining that there should be no failures or defects in work outputs. Philip Crosby popularized the idea, and it forms the basis of his idea of quality.