Measurement of coupling and cohesion of software

Graphs are often used to depict an abstraction of software. A graph may be an abstraction of a software system and a subgraph may represent a software module. Coupling and cohesion are attributes that summarize the degree of interdependence or connectivity among subsystems or within subsystems, respectively. When used in conjunction with measures of other attributes, coupling and cohesion can contribute to an assessment or prediction of software quality. Information theory is attractive to us because the design decisions embodied by the graph are information. Using information theory, we propose measures of the cohesion and coupling of a modular system and cohesion and coupling of each constituent module. These measures conform to the properties of cohesion and coupling defined by Briand, Morasca and Basili, applied to undirected graphs and therefore, are in the families of measures called cohesion and coupling.