In common usage, validation is the process of checking if something satisfies a certain criterion. Examples would include checking if a statement is true (validity), if an appliance works as intended, if a computer system is secure, or if computer data are compliant with an open standard. Validation implies one is able to document that a solution or process is correct or is suited for its intended use.
In engineering or as part of a quality management system, validation confirms that the needs of an external customer or user of a product, service, or system are met. Verification is usually an internalquality process of determining compliance with a regulation, standard, or specification. An easy way of recalling the difference between validation and verification is that validation is ensuring "you built the right product" and verification is ensuring "you built the product right." Validation is testing to confirm that it satisfies stakeholder's or user's needs.
Validation can mean to declare or make legally valid or to prove valid or confirm the validity of data, information, or processes:
In computer terminology, validation refers to the process of data validation, controlling that data inserted into an application satisfies pre determined formats or complies with stated length and character requirements and other defined input criteria.
In the computer architecture and hardware world, validation refers to the process of verifying that the operations of the piece of hardware or architecture meets the specification. In some cases, validation not only refers to finding bugs in the hardware but also proving absence of certain critical bugs which may not have workarounds and may lead to project cancellation or product recall.
In psychology and human communication, validation is the reciprocated communication of respect which communicates that the other's opinions are acknowledged, respected, heard, and (regardless whether or not the listener actually agrees with the content), they are being treated with genuine respect as a legitimate expression of their feelings, rather than marginalized or dismissed.
In research psychology, validation is part of developing a test or questionnaire. A validated test has been shown to measure what it purports to measure, for example, showing that people with high scores on a questionnaire about risk-taking actually do take more risks than people with low scores. Compare to reliability, which means that the different items on a test all get at the same thing.
In the medical device, pharmaceutical and biotechnology manufacturing industries, validation refers to establishing documented evidence that a process or system, when operated within established parameters, can perform effectively and reproducibly to produce a medicinal product meeting its pre-determined specifications and quality attributes (from European Union Good Manufacturing Practices Guide, Annex 15). Regulatory bodies in the U.S., European Union, and Japan (amongst many others) require validation, causing it to become its own sub-industry supporting the pharmaceutical, biotechnology, and medical device industries.
in finance, validation is a process part of the "trade life-cycle."
Validation is important because it disallows data that can not possibly be either true or real to be entered into a database or computer system.
Validation against an incomplete or insufficient set of criteria can lead to a state of "validated" where "validated" does not confer the confidence that the term intends. Thus validation of the validation criteria is an important aspect that is often overlooked. Establishing such validation criteria can be a very difficult task when evaluating complex systems such as Air Traffic Management systems. Establishing "fitness for purpose" is often a more useful concept to support evaluation of complex systems in that the approach focuses on involving stakeholders in establishing and reviewing the purpose that the system must satisfy as the system emerges from early design. This allows flexibility in the evaluation process as ideas turn into detailed designs. Such flexibility is essential in the early development phases in order to avoid engineering white elephants. [The European Operational Concept Validation Methodology E-OCVM provides an approach to validating complex Air Traffic Management systems by establishing fitness for purpose in a world of shifting and incomplete validation criteria].