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A test method is a
method Method ( grc, μέθοδος, methodos) literally means a pursuit of knowledge, investigation, mode of prosecuting such inquiry, or system. In recent centuries it more often means a prescribed process for completing a task. It may refer to: *Scient ...
for a test in
science Science () is a systematic enterprise that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe."... modern science is a discovery as well as an invention. ...

science
or
engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more specializ ...

engineering
, such as a
physical testA physical test is a qualitative or quantitative procedure that consists of determination of one or more characteristics of a given product, process or service according to a specified procedure.ASTM ASTM International, formerly known as American ...
,
chemical test In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they under ...
, or
statistical test A statistical hypothesis is a hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method The scientific method is an Empirical evidence ...
. It is a definitive procedure that produces a test result. In order to ensure accurate and relevant test results, a test method should be "explicit, unambiguous, and experimentally feasible.", as well as effective and reproducible. A test can be considered an
observation Observation is the active acquisition of information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" and thus defines both its essence and the nature of its characteristics. Th ...

observation
or
experiment An experiment is a procedure carried out to support or refute a , or determine the or of something previously untried. Experiments provide insight into by demonstrating what outcome occurs when a particular factor is manipulated. Experime ...

experiment
that determines one or more characteristics of a given sample, product, process, or service. The purpose of testing involves a prior determination of expected observation and a comparison of that expectation to what one actually observes. The results of testing can be qualitative (yes/no), quantitative (a measured value), or categorical and can be derived from personal
observation Observation is the active acquisition of information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" and thus defines both its essence and the nature of its characteristics. Th ...

observation
or the output of a precision
measuring instrument A measuring instrument is a device to measure a physical quantity A physical quantity is a physical property of a material or system that can be Quantification (science), quantified by measurement. A physical quantity can be expressed as a ''va ...

measuring instrument
. Usually the test result is the
dependent variable Dependent and Independent variables are variables in mathematical modeling, statistical modeling and experimental sciences. Dependent variables receive this name because, in an experiment, their values are studied under the supposition or demand ...
, the measured response based on the particular conditions of the test or the level of the
independent variable Dependent and Independent variables are variables in mathematical modeling A mathematical model is a description of a system A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to f ...
. Some tests, however, may involve changing the independent variable to determine the level at which a certain response occurs: in this case, the test result is the independent variable.


Importance

In
software development Software development is the process of conceiving, specifying, designing, programming, documenting, testing, and bug fixing involved in creating and maintaining applications Application may refer to: Mathematics and computing * Application ...
,
engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more specializ ...

engineering
,
science Science () is a systematic enterprise that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe."... modern science is a discovery as well as an invention. ...

science
,
manufacturing Manufacturing is the creation or production Production may be: Economics and business * Production (economics) * Production, the act of manufacturing goods * Production, in the outline of industrial organization, the act of making products (g ...
, and
business Business is the activity of making one's living or making money by producing or buying and selling products (such as goods and services). Simply put, it is "any activity or enterprise entered into for profit." Having a business name A trad ...

business
, its developers, researchers, manufacturers, and related personnel must understand and agree upon methods of obtaining data and making
measurement Measurement is the quantification (science), quantification of variable and attribute (research), attributes of an object or event, which can be used to compare with other objects or events. The scope and application of measurement are dependen ...

measurement
s. It is common for a
physical property A physical property is any property Property is a system of rights that gives people legal control of valuable things, and also refers to the valuable things themselves. Depending on the nature of the property, an owner of property may have th ...
to be strongly affected by the precise method of testing or measuring that property. As such, fully documenting
experiment An experiment is a procedure carried out to support or refute a , or determine the or of something previously untried. Experiments provide insight into by demonstrating what outcome occurs when a particular factor is manipulated. Experime ...

experiment
s and measurements while providing needed documentation and descriptions of
specification A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard A technical standard is an established norm (social), norm or require ...
s,
contract A contract is a legally binding agreement that defines and governs the rights and duties between or among its parties Image:'Hip, Hip, Hurrah! Artist Festival at Skagen', by Peder Severin Krøyer (1888) Demisted with DXO PhotoLab Clearview ...

contract
s, and test methods is vital. Using a
standardized Standardization or standardisation is the process of implementing and developing technical standard A technical standard is an established norm or requirement for a repeatable technical task. It is usually a formal document that establishes un ...
test method, perhaps published by a respected
standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization (SSO) is an organization whose primary function is developing, coordinating, promulgating, revising, amending, reissuing, interpr ...
, is a good place to start. Sometimes it is more useful to modify an existing test method or to develop a new one, though such home-grown test methods should be validated and, in certain cases, demonstrate technical equivalency to primary, standardized methods. Again, documentation and full disclosure are necessary. A well-written test method is important. However, even more important is choosing a method of measuring the correct property or characteristic. Not all tests and measurements are equally useful: usually a test result is used to predict or imply suitability for a certain purpose. For example, if a manufactured item has several components, test methods may have several levels of connections: * test results of a raw material should connect with tests of a component made from that material * test results of a component should connect with
performance testingPerformance test or performance testing may refer to: * Performance test (assessment), an assessment requiring the subject to perform a task or activity * Performance test (bar exam), a section of the bar exam simulating a real-life legal task * Sof ...
of a complete item * results of laboratory performance testing should connect with field performance These connections or
correlation In , correlation or dependence is any statistical relationship, whether or not, between two s or . In the broadest sense correlation is any statistical association, though it actually refers to the degree to which a pair of variables are rel ...

correlation
s may be based on published literature, engineering studies, or formal programs such as
quality function deploymentQuality function deployment (QFD) a method developed in Japan beginning in 1966 to help transform the voice of the customer Voice of the customer (VOC) is a term used in business and Information Technology (through ITIL, for example) to describe the ...
. Validation of the suitability of the test method is often required.


Content

Quality management system A quality management system (QMS) is a collection of business process A business process, business method or business function is a collection of related, structured activities or tasks Task may refer to: * Task (project management), an activit ...
s usually require full documentation of the procedures used in a test. The document for a test method might include: * descriptive title * scope over which class(es) of items, policies, etc. may be evaluated * date of last effective revision and revision designation * reference to most recent test method validation * person, office, or agency responsible for questions on the test method, updates, and deviations * significance or importance of the test method and its intended use * terminology and definitions to clarify the meanings of the test method * types of apparatus and measuring instrument (sometimes the specific device) required to conduct the test *
sampling Sampling may refer to: *Sampling (signal processing), converting a continuous signal into a discrete signal *Sample (graphics), Sampling (graphics), converting continuous colors into discrete color components *Sampling (music), the reuse of a sound ...
procedures (how samples are to be obtained and prepared, as well as the
sample size Sample size determination is the act of choosing the number of observations or replicates to include in a statistical sample In statistics and quantitative research methodology, a sample is a set of individuals or objects collected or selected ...
) *
safety Safety is the state of being "safe", the condition of being protected from harm Harm is a moral A moral (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages ...

safety
precautions * required
calibration In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a Standard (metrology), calibration standard of known accuracy. Such a standard could be another measuremen ...

calibration
s and
metrology Metrology is the scientific study of measurement ' Measurement is the number, numerical quantification (science), quantification of the variable and attribute (research), attributes of an object or event, which can be used to compare with oth ...

metrology
systems *
natural environment The natural environment or natural world encompasses all life, living and non-living things occurring nature, naturally, meaning in this case not Artificiality, artificial. The term is most often applied to the Earth or some parts of Earth. Th ...

natural environment
concerns and considerations * testing environment concerns and considerations * detailed procedures for conducting the test * calculation and analysis of data * interpretation of data and test method output * report format, content, data, etc.


Validation

Test methods are often scrutinized for their validity, applicability, and accuracy. It is very important that the scope of the test method be clearly defined, and any aspect included in the scope is shown to be accurate and repeatable through validation. Test method validations often encompass the following considerations: *
accuracy and precision In a set of measurements, accuracy is closeness of the measurements to a specific value, while precision is the closeness of the measurements to each other. ''Accuracy'' has two definitions: # More commonly, it is a description of ''systematic er ...

accuracy and precision
; demonstration of accuracy may require the creation of a reference value if none is yet available *
repeatability Repeatability or test–retest reliability is the closeness of the agreement between the results of successive measurements ' Measurement is the number, numerical quantification (science), quantification of the variable and attribute (research), att ...
and
reproducibility Reproducibility, also known as replicability and repeatability, is a major principle underpinning the scientific method The scientific method is an Empirical evidence, empirical method of acquiring knowledge that has characterized the develop ...
, sometimes in the form of a Gauge R&R. * range, or a continuum scale over which the test method would be considered accurate (e.g., 10 N to 100 N force test) *
measurement resolution In the broadest definition, a sensor is a device, module, machine, or subsystem whose purpose is to detect events or changes in its environment and send the information to other electronics, frequently a computer processor A central proc ...
, be it spatial, temporal, or otherwise *
curve fitting Curve fitting is the process of constructing a curve In mathematics, a curve (also called a curved line in older texts) is an object similar to a line (geometry), line, but that does not have to be Linearity, straight. Intuitively, a curve ma ...

curve fitting
, typically for linearity, which justifies
interpolation In the mathematical Mathematics (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its populatio ...

interpolation
between calibrated reference points * robustness, or the insensitivity to potentially subtle variables in the test environment or setup which may be difficult to control * usefulness to predict end-use characteristics and performance *
measurement uncertainty In metrology 290px, alt=Man in white standing in front of a large machine, A scientist stands in front of the Microarcsecond Metrology (MAM) testbed. Metrology is the scientific study of measurement ' Measurement is the number, numerical qua ...
* interlaboratory or
round robin testIn experimental methodology, a round robin test is an interlaboratory test (measurement, analysis, or experiment An experiment is a procedure carried out to support, refute, or validate a hypothesis. Experiments provide insight into Causality, ...
s * other types of
measurement systems analysis A measurement systems analysis (MSA) is a thorough assessment of a measurement process, and typically includes a specially designed experiment An experiment is a procedure carried out to support, refute, or validate a hypothesis. Experiments p ...


See also

*
Certified reference materials Certified Reference Materials (CRMs) are ‘controls’ or standards used to check the quality and metrological traceability Image:Microarcsecond testbed.jpg, 290px, alt=Man in white standing in front of a large machine, A scientist stands in f ...
*
Data analysis Data analysis is a process of inspecting, cleansing, transforming, and modelling In general, a model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century Engl ...
*
Design of experiments The design of experiments (DOE, DOX, or experimental design) is the design of any task that aims to describe and explain the variation of information under conditions that are hypothesized to reflect the variation. The term is generally associ ...
*
Document management system A document management system (DMS) is a system used to receive, track, manage and store documents and reduce paper. Most are capable of keeping a record of the various versions created and modified by different users (history tracking). In the cas ...
* EPA Methods *
Integrated test facility An integrated test facility (ITF) creates a fictitious entity in a database to process test transactions simultaneously with live input. ITF can be used to incorporate test transactions into a normal production run of a system. Its advantage is t ...
*
Measurement systems analysis A measurement systems analysis (MSA) is a thorough assessment of a measurement process, and typically includes a specially designed experiment An experiment is a procedure carried out to support, refute, or validate a hypothesis. Experiments p ...
*
Measurement uncertainty In metrology Metrology is the scientific study of measurement ' Measurement is the number, numerical quantification (science), quantification of the variable and attribute (research), attributes of an object or event, which can be used to c ...
*
Metrication Metrication or metrification is the act or process of converting to a metric METRIC (Mapping EvapoTranspiration at high Resolution with Internalized Calibration) is a computer model Computer simulation is the process of mathematical model ...

Metrication
*
Observational error Observational error (or measurement error) is the difference between a measured value of a quantity and its true value.Dodge, Y. (2003) ''The Oxford Dictionary of Statistical Terms'', OUP. In statistics Statistics is the discipline that co ...
*
Replication (statistics) In engineering, science, and statistics, replication is the repetition of an experimental condition so that the variability associated with the phenomenon can be estimated. ASTM, in International standard, standard E1847, defines replication as "the ...
*
Sampling (statistics) In statistics Statistics is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data Data (; ) are individual facts, statistics, or items of information, often numeric. In a ...
*
Specification (technical standard) A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard A technical standard is an established norm (social), norm or require ...
* Test management approach *
Verification and validation Verification and validation (also abbreviated as V&V) are independent procedures that are used together for checking that a product, service, or system meets requirement In product development and process optimization, a requirement is a sing ...


References


General references, books

* Pyzdek, T, "Quality Engineering Handbook", 2003, * Godfrey, A. B., "Juran's Quality Handbook", 1999, * Kimothi, S. K., "The Uncertainty of Measurements: Physical and Chemical Metrology: Impact and Analysis", 2002, {{ISBN, 0-87389-535-5


Related standards

* ASTM E177 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods * ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method * ASTM E1488 Standard Guide for Statistical Procedures to Use in Developing and Applying Test Methods * ASTM E2282 Standard Guide for Defining the Test Result of a Test Method * ASTM E2655 - Standard Guide for Reporting Uncertainty of Test Results and Use of the Term Measurement Uncertainty in ASTM Test Methods Metrology Measurement Quality control *