This paper presents how the non-homogeneous Poisson Process (NHPP), based on the Crow-AMSAA model (test-fix-test), can be used to evaluate the reliability of the whole Quality Management System (QMS) and the quality strategies of a business unit, within a certain observed period. This approach can quantify and provide statistical evidence if a QMS reliability is growing or not. It can also help to establish key quality indicators that are directly linked to customer satisfaction and their quality perception about the company.