Item response theory is a way to analyze responses to tests or questionnaires, measuring abilities, attributes or other variables, with the goal of improving measurement accuracy and reliability. It is also termed as latent trait theory, strong true score theory, or modern mental test theory.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.