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A test method is a definitive procedure that produces a test result. (ASTM definition)

The test result can be qualititive (yes/no), categorical, or quantititive (a measured value). It can be a personal observation or the output of a precision measuring instrument
Measuring instrument

In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantity of real-world object and phenomenon....
.

Usually the test result is the dependent variable, the measured response based on the particular conditions of the test or the level of the independent variable
Independent variable

The terms "dependent variable" and "independent variable" are used in similar but subtly different ways in mathematics and statistics as part of the standard terminology in those subjects....
.






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A test method is a definitive procedure that produces a test result. (ASTM definition)

The test result can be qualititive (yes/no), categorical, or quantititive (a measured value). It can be a personal observation or the output of a precision measuring instrument
Measuring instrument

In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantity of real-world object and phenomenon....
.

Usually the test result is the dependent variable, the measured response based on the particular conditions of the test or the level of the independent variable
Independent variable

The terms "dependent variable" and "independent variable" are used in similar but subtly different ways in mathematics and statistics as part of the standard terminology in those subjects....
. Some tests, however, 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 of test methods


In engineering
Engineering

Engineering is the discipline and profession of applying Technology and science knowledge and utilizing natural laws and physical resources in order to design and implement materials, structures, machines, devices, systems, and process that safely realize a desired objective and meet specified criteria....
, science
Science

In its broadest sense, science refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research....
, manufacturing
Manufacturing

Manufacturing is the use of machine, tool and labor to make things for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to Industry production, in which raw material are transformed into finished good on a large scale....
, and business
Business

A business is a legally recognized organization designed to provide good s and/or Service to consumers. Businesses are predominant in capitalism economies, most being privately owned and formed to earn profit that will increase the wealth of its owners....
, it is vital for all interested people to understand and agree upon methods of obtaining data and making measurement
Measurement

Measurement is the process of assigning a number to an attribute according to a rule or set of rules. The term can also be used to refer to the result obtained after performing the process....
s. For example, is common for a physical property
Physical property

A physical property is any aspect of an object or substance that can be measurement or perception without changing its Identity . Physical properties can be Intensive and extensive properties....
 to be strongly affected by the precise method of testing or measuring that property. It is vital to fully document experiments and measurement
Measurement

Measurement is the process of assigning a number to an attribute according to a rule or set of rules. The term can also be used to refer to the result obtained after performing the process....
s and to provide needed definition to specifications and contract
Contract

A contract is an exchange of promises between two or more parties to do, or refrain from doing, an act which is enforceable in a court of law. It is a binding legal agreement....
s.

Using a standard
Standard

A technical standard is an established norm or requirement. It is usually a formal document that establishes uniform engineering or technical criteria, methods, processes and practices....
 test method, perhaps published by a respected standards organization
Standards organization

A standards organization, standards body, standards development organization or SDO is any entity whose primary activities are developing, coordinating, promulgating, revising, amending, reissuing, interpreting, or otherwise maintaining standards that address the interests of a wide base of users outside the standards develo...
, is a good place to start. Sometimes it is more useful to modify one or to develop a new one. Again, documentation and full disclosure are very 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 sutiability 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 testing
    Performance testing

    In software engineering, performance testing is Software testing that is performed, from one perspective, to determine how fast some aspect of a system performs under a particular workload....
     of a complete item
  • results of laboratory performance testing should connect with field performance
  • etc


These connections or correlation
Correlation

In probability theory and statistics, correlation indicates the strength and direction of a linear relationship between two random variables....
s may be based on published literature, engineering studies, or formal programs such as quality function deployment
Quality function deployment

Quality function deployment is a ?method to transform user demands into design quality, to deploy the functions forming quality, and to deploy methods for achieving the design quality into subsystems and component parts, and ultimately to specific elements of the manufacturing process.? , as described by Dr....
. Validation
Validation

The word validation has several uses:* In common usage, validation is the process of checking if something satisfies a certain criterion. Examples would include checking if a statement is true , if an appliance works as intended, if a computer system is secure, or if computer data are compliant with an open standard....
 of the suitability of the test method is often required.

Content of a test method


The test method might include:

  • Descriptive title and scope of the test method
  • Date of last effective revision and revision designation
  • Person, office, or agency responsible for questions on the test method, updates, and deviations.
  • The significance or importance of the test method and its intended use.
  • Terminology and definition
    Definition

    A definition is a statement of the Meaning of a word or phrase. The term to be defined is known as the definiendum . The words which define it are known as the definiens ....
    s to clarify the meanings of the test method
  • A listing of the types of apparatus and measuring instrument
    Measuring instrument

    In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantity of real-world object and phenomenon....
     (sometimes the specific device) required to conduct the test
  • Safety
    Safety

    Safety is the state of being "safe" , the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be considered non-desirable....
     precautions
  • Required calibration
    Calibration

    Calibration is the validation of specific measurement techniques and equipment. At the simplest level, calibration is a comparison between measurements-one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device....
    s and metrology
    Metrology

    Metrology is the science of measurement. Metrology includes all theoretical and practical aspects of measurement....
     systems
  • Environmental
    Natural environment

    The natural environment, commonly referred to simply as the environment, is a term that encompasses all life and non-living things occurring nature on Earth or some region thereof....
     concerns and considerations
  • Sampling procedures. How are samples to be obtained. Number of samples.
  • Conditioning: temperature
    Temperature

    In physics, temperature is a physical property of a Physical system that underlies the common notions of hot and cold; something that feels hotter generally has the greater temperature....
    , humidity
    Humidity

    Humidity is the amount of water vapor in the air. In daily language the term "humidity" is normally taken to mean relative humidity. Relative humidity is defined as the ratio of the partial pressure of water vapor in a Air parcel of air to the saturated vapor pressure of water vapor at a prescribed temperature....
    , etc, and Tolerance (engineering)
    Tolerance (engineering)

    Engineering tolerance is the permissible limit of variation in# a physical dimension,# a measured value or physical property of a material, manufacturing object, system, or service,...
  • Preparation of samples for the test
  • Detailed procedure for conducting the test
  • Calculations and analysis of data
  • Interpretation of data and test method output
  • Report: format, content, data, etc
  • Accuracy, precision, systematic bias
    Systematic bias

    In metrology, dynamical systems theory, computational mechanics, and statistics, a systematic bias is a bias of a measurement system or estimate method, which leads to systematic errors, namely produces readings or results which are consistently too high or too low, relative to a given actual value of the measured or estimated variable....
    , repeatability
    Repeatability

    Repeatability is the variation in measurements taken by a single person or Measuring instrument on the same item and under the same conditions. A measurement may be said to be repeatable when this variation is smaller than some agreed limit....
    , reproducibility
    Reproducibility

    Reproducibility is one of the main principles of the scientific method, and refers to the ability of a test or experiment to be accurately reproduced, or replicated, by someone else working independently....
    , and uncertainty
    Uncertainty

    Uncertainty is a term used in subtly different ways in a number of fields, including philosophy, Uncertainty_principle , statistics, economics, finance, insurance, psychology, sociology, engineering, and information science....
     of test results


See also

  • Certified reference materials
    Certified reference materials

    Certified Reference Materials are ?controls? or standards used to check the quality and traceability of products. A reference standard for a unit of measurement is an artifact that embodies the quantity of interest in a way that ties its value to the reference base for calibration....
  • Data analysis
    Data analysis

    Data analysis is a process of gathering, modeling, and transforming data with the goal of highlighting useful information, suggesting conclusions, and supporting decision making....
  • Design of experiments
    Design of experiments

    Design of experiments, or experimental design, is the design of all information-gathering exercises where variation is present, whether under the full control of the experimenter or not....
  • Experiment
    Experiment

    In scientific inquiry, an experiment is a method of investigating causal relationships among variables. An experiment is a cornerstone of the empiricism approach to acquiring data about the world and is used in both natural sciences and social sciences....
  • Measurement Systems Analysis
    Measurement Systems Analysis

    A Measurement System Analysis, abbreviated MSA, is a specially designed experiment that seeks to identify the components of variation in the measurement....
  • Measurement uncertainty
    Measurement uncertainty

    In metrology, measurement uncertainty describes a region about an observed value of a physical quantity which is likely to enclose the true value of that quantity....
  • Metrication
    Metrication

    Metrication refers to the introduction of the Metric system as the international standard for physical measurements?a long-term series of independent and systematic conversions from the various separate localism systems of historical weights and measures....
  • Metrology
    Metrology

    Metrology is the science of measurement. Metrology includes all theoretical and practical aspects of measurement....
  • Observational error
    Observational error

    Observational error is the difference between a measurement value of quantity and its true value. In statistics, an error is not a "mistake". Variability is an inherent part of things being measured and of the measurement process....
  • Performance testing
    Performance testing

    In software engineering, performance testing is Software testing that is performed, from one perspective, to determine how fast some aspect of a system performs under a particular workload....
  • Replication (statistics)
    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....
  • Sampling (statistics)
    Sampling (statistics)

    Sampling is that part of statistical practice concerned with the selection of individual observations intended to yield some knowledge about a population of concern, especially for the purposes of statistical inference....
  • Specification (technical standard)
    Specification (technical standard)

    A specification is an explicit set of requirements to be satisfied by a material, product, or service. ...
  • Tolerance (engineering)
    Tolerance (engineering)

    Engineering tolerance is the permissible limit of variation in# a physical dimension,# a measured value or physical property of a material, manufacturing object, system, or service,...
  • Verification and Validation?