Mathematical Validation of Object-Oriented Class Cohesion Metrics

Abstract

Class cohesion is an object-oriented software quality attribute and refers to the extent to which the members of a class are related. Software developers use class cohesion measures to assess the quality of their products and to guide the restructuring of poorly designed classes. Several class cohesion metrics are proposed in the literature, and a few of them are mathematically validated against the necessary properties of class cohesion. Metrics that violate class cohesion properties are not well defined, and their utility as indictors of the relatedness of class members is questionable. The purpose of this paper is to mathematically validate sixteen class cohesion metrics using class cohesion properties. Results show that metrics differ considerably in satisfying the cohesion properties; some of them satisfy all properties, while others satisfy none.