Clone Stability

Code clones are said to threaten the maintainability of a system -- especially when the system evolves and source code is changed. Whether clones truly increase maintenance effort can be analyzed by comparing the stability of cloned code to the stability of non-cloned code. A previous study found that cloned code is even more stable than non-cloned code and, thus, requiring less maintenance effort -- contrary to the frequently voiced assumption. In this paper, we describe our partial replication and extension of this study using a more detailed measurement and considering different parameters for clone detection. In general, we were able to validate the findings of the previous study. We furthermore explored possible reasons to gain a better understanding of the unintuitive results.