Software validation : is performed 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.
Software validation is achieved through a series of tests that demonstrate conformity with requirements. A test plan outlines the classes of tests to be conducted, and a test procedure defines specific test cases that are designed to ensure that all functional requirements are satisfied, all behavioral characteristics are achieved, all content is accurate and properly presented, all performance requirements are attained, documentation is correct, and usability and other requirements are met (e.g., transportability,
compatibility, error recovery, maintainability). After each validation test case has been conducted, one of two possible conditions exists:
(1) The function or performance characteristic conforms to specification and is accepted or
(2) a deviation from specification is uncovered and a deficiency list is created.
Deviations or errors discovered at this stage in a project can rarely be corrected prior to scheduled delivery. .
Reference :- Pressman Page no 468