Osman Ceylan, Senior Application Engineer at Maury Microwave, discusses the concepts behind the classical VNA measurement model and the evolution to an enhanced model that includes uncertainties, including how to identify and characterize each major contributor of uncertainty. Osman then proceeds to discuss how uncertainty can be used to improve the VNA calibration validation process. Finally, he shows examples and use-cases of how measurement uncertainties can impact the interpretation of our measurement data.