The technique of software defect prediction aims to assess and predict potential defects in software projects and has made significant progress in recent years within software development. In previous studies, this technique largely relied on supervised learning methods, requiring a substantial amount of labeled historical defect data to train the models. However, obtaining these labeled data often demands significant time and resources. In contrast, software defect prediction based on unsupervised learning does not depend on known labeled data, eliminating the need for large‐scale data labeling, thereby saving considerable time and resources while providing a more flexible solution for ensuring software quality. This paper conducts software defect prediction using unsupervised learning methods on data from 16 projects across two public datasets (PROMISE and NASA). During the feature selection step, a chi‐squared sparse feature selection method is proposed. This feature selection strategy combines chi‐squared tests with sparse principal component analysis (SPCA). Specifically, the chi‐squared test is first used to filter out the most statistically significant features, and then the SPCA is applied to reduce the dimensionality of these significant features. In the clustering step, the dot product matrix and Pearson correlation coefficient (PCC) matrix are used to construct weighted adjacency matrices, and a clustering overlap method is proposed. This method integrates spectral clustering, Newman clustering, fluid clustering, and Clauset–Newman–Moore (CNM) clustering through ensemble learning. Experimental results indicate that, in the absence of labeled data, using the chi‐squared sparse method for feature selection demonstrates superior performance, and the proposed clustering overlap method outperforms or is comparable to the effectiveness of the four baseline clustering methods.
