validation

Validation is the process of establishing evidence that a product, service, process, or system fulfills its intended use and meets predefined requirements. It answers the question of whether the thing being validated is suitable for its purpose in real-world conditions. Validation is often contrasted with verification, which asks whether a product was built correctly according to its design specifications. In practice, validation focuses on fitness for use and overall outcomes, while verification focuses on conformity to design.

In software and systems, validation involves activities that demonstrate the end product satisfies user needs and regulatory requirements. This can include planning, requirements analysis, testing, usability evaluation, and acceptance testing. In manufacturing and life sciences, validation is a formal process that may require documented evidence from installation, operation, and performance testing, sometimes guided by standards such as GMP or ISO 9001. Equipment qualification, including Installation Qualification, Operational Qualification, and Performance Qualification, is a related concept used to prove that facilities and tools perform as intended.

Data validation refers to methods that ensure data quality, including accuracy, validity, consistency, and completeness. Techniques include input validation, rule-based checks, data cleaning, and validation against reference datasets.

Model and experimental validation involve comparing outputs or predictions to independent data or real-world observations to establish credibility and predictive usefulness. Validation is typically documented in a validation plan and report, emphasizes risk-based approaches, and may be subject to regulatory or organizational governance. Continuous validation may be warranted as requirements or environments change.