Complexity Metrics Significance for Defects: An Empirical View

Software Complexity often seems to be correlated with the defects and this makes difficult to select appropriate complexity metrics that would be effec-tive indicators of defects. The aim of this work is to analyze the relationship of different complexity metrics with the defects for three categories of software pro-jects i.e. large, medium and small. We analyzed 18 complexity metrics and defects from 27,734 software modules of 38 software projects categorized in large, me-dium and small. In all categories of projects we do not find any strong positive correlation between complexity metrics and defects. However we cluster the com-plexity metric values and defects in three categories as high, medium and low. Consequently we observe that for some complexity metrics high complexity re-sults in higher defects. We called these metrics as effective indicators of defects. In the small category of projects we found LCOM as effective indicator, in the medium category of project we found WMC, CBO, RFC, CA, CE, NPM, DAM, MOA, IC, Avg CC as effective indicators of defects and for a large category of projects we found WMC, CBO, RFC, CA, NPM, AMC, Avg CC as effective indi-cators of defects. The difference shows that complexity metrics relation to defects also varies with the size of projects.