Exploring the Relationship between Cohesion and Complexity

Many metrics have been proposed to measure the complexity or cohesion of object-oriented software. However, the complexity or cohesion of a piece of software is more difficult to capture than these metrics imply. In fact, studies have shown that existing metrics consistently fail to capture complexity or cohesion well. This study explores the reasons behind these results: cohesion is difficult to capture from syntactic elements of code, complexity is too multi-faceted to be captured by one metric and the qualities of complexity and cohesion are not independent. These factors have resulted in metrics that are purported to measure complexity or cohesion but are inadequate or misclassified. This study shows that there is overlap between some of the complexity and cohesion metrics and points to a more basic relationship between complexity and cohesion: that a lack of cohesion may be associated with high complexity.