A Proposal for Normalized Lack of Cohesion in Method (LCOM) Metric Using Field Experiment

Chidamber and Kemerer first defined a cohesion measure for object-oriented software – the Lack of Cohesion in Methods (LCOM) metric. One of the critique of the LCOM metric is that the metric does not yield normalized or standardized values, and as such, the metric does not seem appealing to a section of the software engineering community. This paper presents an approach for normalizing the LCOM metric so that most practioners would find it as useful as its variant measures such as Tight Class Cohesion (TCC), Low Class Cohesion (LCC), Degree of Cohesion in a Class based on direct relation between its public relations (DCD) and that based on indirect methods (DCI). Data for this study was gathered from three industrial systems. System 1 has 34 classes, System 2 has 383 classes and System 3 has 1055 classes. The main objectives of the study were to apply different normalization approaches in order to determine the best for the LCOM metric. Three normalization techniques namely Sigmoid normalization, Bowless normalization, and Bestfit normalization were used in the study of the selected test systems. The result of the study showed that the Bestfit approach seem to be the best LCOM normalization approach.