Revising cohesion measures by considering the impact of write interactions between class members

Cohesion refers to the degree of the relatedness of the members in a class and several cohesion measures have been proposed to quantify the cohesiveness of classes in an object-oriented program. However, the existing cohesion measures do not differentiate write interactions from read interactions between class members, thus, do not properly reflect the cohesiveness of the class. This paper presents the revised versions of the existing five cohesion measures by considering the impact of write interactions between class members. In addition, we prove that the revised measures can be reduced into the original ones. To demonstrate the importance of write interactions, we have developed tools for automatic computation of the original and the revised cohesion measures and performed a case study where we found that write interactions are so commonly used in classes that they have much influence on cohesion measurement and the revised measures have stronger relations with change-proneness of classes than the original ones.