Inferring developer expertise through defect analysis

Fixing defects is an essential software development activity. For commercial software vendors, the time to repair defects in deployed business-critical software products or applications is a key quality metric for sustained customer satisfaction. In this paper, we report on the analysis of about 1,500 defect records from an IBM middle-ware product collected over a five-year period. The analysis includes a characterization of each repaired defect by topic and a ranking of developers by inferred expertise on each topic. We find clear evidence that defect resolution time is strongly influenced by a specific developer and his/her expertise in the defect´s topic. To validate our approach, we conducted interviews with the product´s manager who provided us with his own ranking of developer expertise for comparison. We argue that our automated developer expertise ranking can be beneficial in the planning of a software project and is applicable beyond software support in the other phases of the software lifecycle.