Verification versus Validation:

Verification and Validation are the two forms of testing software.

Verification ensures that the system (software, hardware, documentation, and personnel) complies with an organization’s standards and processes, relying on review of non-executable methods.

Validation physically ensures that the system operates according to plan by executing the system functions through a series of tests that can be observed and evaluated.

Verification answers the question, “Did we build the right system?” while validation addresses, “Did we build the system right?”

Verification requires several types of reviews, including requirements reviews, design reviews, code walkthroughs, code inspections, and test reviews. The system user should be involved in these reviews to find defects before they are built into the system. In the case of purchased systems, user input is needed to assure that the supplier makes the appropriate tests to eliminate defects.

Validation is accomplished simply by executing a real-life function. This includes unit testing, integration testing, system testing and user acceptance testing. In this rigorous testing is conducted to validate if the system meets the functional requirement.