The impact of IR-based classifier configuration on the performance and the effort of method-level bug localization.

•Investigating the impact of the IR-based classifier configuration on the top-k performance and the required effort.•Investigating whether the most efficient classifier configuration for file-level bug localization is also the most efficient at the method-level.•We execute a large space of classifier configuration, 3,172 in total, on 5,266 bug reports of two software systems, i.e., Eclipse and Mozilla.•The configuration has a large impact on both the top-k performance and the required effort for method-level bug localization.•IR-based configuration settings should be carefully selected and the required effort metrics should be included in future bug localization studies.