Atest method is a method for a test in scienceorengineering, such as a physical test, chemical test, or statistical test. It is a definitive procedure that produces a test result.[1] In order to ensure accurate and relevant test results, a test method should be "explicit, unambiguous, and experimentally feasible.",[2] as well as effective[3] and reproducible.[4]
A test can be considered an observationorexperiment 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.[5] The results of testing can be qualitative (yes/no), quantitative (a measured value), or categorical and can be derived from personal observation or the output of a precision measuring instrument.
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. 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.
Insoftware development, engineering, science, manufacturing, and business, its developers, researchers, manufacturers, and related personnel must understand and agree upon methods of obtaining data and making measurements. It is common for a physical property to be strongly affected by the precise method of testing or measuring that property. As such, fully documenting experiments and measurements while providing needed documentation and descriptions of specifications, contracts, and test methods is vital.[6][2]
Using a standardized test method, perhaps published by a respected standards organization, 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[4] and, in certain cases, demonstrate technical equivalency to primary, standardized methods.[6] Again, documentation and full disclosure are necessary.[2]
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.[2][3] 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 of a complete item
results of laboratory performance testing should connect with field performance
These connections or correlations may be based on published literature, engineering studies, or formal programs such as quality function deployment. Validation of the suitability of the test method is often required.[4]
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.[4][7][9][10]
Test method validations often encompass the following considerations:[2][4][7][9][10]
accuracy and precision; demonstration of accuracy may require the creation of a reference value if none is yet available
^ abOffice of Regulatory Science (12 May 2014). "5.4 Test Methods and Method Validation"(PDF). Laboratory Manual Of Quality Policies For ORA Regulatory Laboratories: Volume 1. U.S. Food and Drug Administration. Retrieved 8 February 2018.
