An empirical study of data sampling techniques for just-in-time software defect prediction

Just-in-time software defect prediction (JIT-SDP) is a fine-grained, easy-to-trace, and practical method. Unfortunately, JIT-SDP usually suffers from the class imbalance problem, which affects the performance of the models. Data sampling is one of the commonly used class imbalance techniques to overcome this problem. However, there is a lack of comprehensive empirical studies to compare different data sampling techniques on the performance of JIT-SDP. In this paper, we consider both defect classification and defect ranking, two typical application scenarios. To this end, we performed an empirical comparison of 10 data sampling algorithms on the performance of JIT-SDP. Extensive experiments on 10 open-source projects with 12 performance measures show that the effectiveness of data sampling techniques can indeed vary relying on the specific evaluation measures in both defect classification and defect ranking scenarios. Specifically, the RUM algorithm has demonstrated superior performance overall in the context of defect classification, particularly in F-measure, AUC, and MCC. On the other hand, for defect ranking, the ENN algorithm has emerged as the most favorable option, exhibiting perfect results in \(P_{opt}\) $P_{\mathit{opt}}$ , Recall@20%, and F-measure@20%. However, data sampling techniques can lead to an increase in false alarms and require the inspection of a higher number of changes. These findings highlight the importance of carefully selecting the appropriate data sampling technique based on the specific evaluation measures for different scenarios.