As project outputs are completed, do an internal assessment within the project team, inspecting, examining, and checking the results. Identify any defects or problems and revise your plans to correct the deficiencies.
When project deliverables require external validation, conduct tests to verify that the deliverables meet all the requirements set by the people who must sign off on them.
If the project deliverables are consistent with the specifications, get formal approval. If the deliverables fail to meet the measurement standards, do one of the following:
Address the issues promptly and obtain sign-off
Negotiate project changes consistent with results and obtain sign-off
Capture status information and plan for additional effort ...