Verification is about building something correctly. Verification process determines if the product is correctly built or not as described in procedure manuals and if all quality assurance and quality control activities are being performed as they are supposed to be. Verification process checks that the product is being developed with all specifications appropriately while meeting all documented specifications or not. It is an objective process where product specifications and all quality requirements are documented well enough so that they could be measured and analyzed. It is about evaluating the process and product in development. It is performed to build a product in the right way. Document reviews and inspection are examples of the verification process activities. I think verification can be done in any phase of the project even though it is usually done in execution phase. Verification in every phase will assist if any change is required or not in any phase. So any major changes can be prevented and it will also save the resources and cost of the project.