Verification vs Validation

VERIFICATION vs VALIDATION is hugely confused and debated in the software industry. You will encounter (or have encountered) all kinds of usage and interpretations of these terms, and it is our humble attempt here to distinguish between them as clearly as possible.

Verification Definition

  • ISTQB®: Confirmation by examination and through provision of objective evidence that specified requirements have been fulfilled.
  • PMBOK® : The evaluation of whether or not a product, service, or system complies with a regulation, requirement, specification, or imposed condition. It is often an internal process. Contrast with validation.

Validation Definition

  • ISTQB®: Confirmation by examination and through provision of objective evidence that the requirements for a specific intended use or application have been fulfilled.
  • PMBOK® : The assurance that a product, service, or system meets the needs of the customer and other identified stakeholders. It often involves acceptance and suitability with external customers. Contrast with verification.


DefinitionThe process of evaluating work-products (not the actual final product) of a development phase to determine whether they meet the specified requirements for that phase.The process of evaluating software during or at the end of the development process to determine whether it satisfies specified business requirements, needs or expectations.
ObjectiveTo ensure that the product is being built according to the requirements and design specifications. In other words, to ensure that work products meet their specified requirements.To ensure that the product actually meets the user’s needs and that the specifications were correct in the first place. In other words, to demonstrate that the product fulfills its intended use when placed in its intended environment.
QuestionAre we building the product right?Are we building the right product?
Evaluation ItemsPlans, Requirement Specs, Design Specs, Code, Test CasesThe actual product / software.
  • Reviews
  • Walkthroughs
  • Inspections
  • Testing


It is entirely possible that a product passes when verified but fails when validated. This can happen when, say, a product is built as per the specifications but the specifications themselves fail to address the user’s needs.

  • Trust but Verify.
  • Verify but also Validate.

Still confused?

It will be more clear after learning about QUALITY ASSURANCE vs QUALITY CONTROL.

Last Updated on March 15, 2023 by STF