Comparison of Fixing Frequency between Duplicate Code and Non-Duplicate Code

Comparison of Fixing Frequency between Duplicate Code and Non-Duplicate Code Yukiko SANO†, Yoshiki HIGO†, and Shinji KUSUMOTO† † Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita-shi, 565-0871 Japan E-mail: †{y-sano,higo,kusumoto}@ist.osaka-u.ac.jp Abstract In general, it is said that duplicate code is modified more frequently than non-duplicate code. However, there are few quantitative studies invstigating whether it is true. Furthermore, the previous studies investigated on the unit of programming language such as file or method, not on duplicate code itself, so that there is a possibility that modifications that are not related to duplicate code are regarded as ones that are related to duplicate code. In addition, only a small number of software systems were investigated. In this paper, therefore, to measure modification frequency more accurately, we investigated modification frequency of duplicate code and non-duplicate code by line. Also, to obtain more general results, experiments conducted on various types of software systems.