Impact of Version History Metrics on Maintainability

In this study we present how some version control history based metrics affect maintainability of the source code. These metrics cover intensity of modifications, code ownership and code aging. We determine the order of source files based on each analyzed metrics, and compare it with their maintainability based order. As a cross-check we perform a comparison test with post-release defects as well. We performed the analysis on 14 versions of 4 well-known open source software systems. The results show high correlation between the version control metrics and relative maintainability indexes, in each case. The comparison with post-release defects also support the results in most of the cases.