The item response theory (IRT), also known as the latent response theory refers to a family of mathematical models that attempt to explain the relationship between latent traits (unobservable characteristic or attribute) and their manifestations (i.e. observed outcomes, responses or performance). They establish a link between the properties of items on an instrument, individuals responding to these items and the underlying trait being measured.The responses in Item Response theory are binary responses where one can either get a question right or wrong in ability tests or ordinal where this is a degree of agreement on a rating scale. IRT models have been traditionally used to analyze these types of responses in psychological assessments and educational testing. These models help us to improve accuracy and also economize test administration by adaptively using only the discriminative items.IRT has been increasingly popular in the fields of medical research, health sciences, quality of life survey and even marketing research due to the above properties. There three types of item response theory models namely Rasch model, two-parameter model and graded response model. However, in this paper we shall focus on the graded response model of customer satisfaction and its application in the ordinal scale of the quality of life survey in the University Of Nairobi.