I disagree with the posts above. The verification and validation covers all phases of the product development cycle. Its really critical to start the verification and validation at the beginning to establish the user needs and product specification. During the product development, verification is done to see if the product design input satisfies the product design output. Process verification is also completed to establish If the process input matches the process output. Finally during the end stages of the project, validation is done to conclude that the end product meets the user’s requirements.