Coverage-based software reliability growth models (SRGMs) have been developed and successfully applied in practice. Performance of a coverage-based SRG M depends on the coverage function employed by the SRGM. When the coverage function represents the coverage growth behavior well irrespective of type of the testing profile the corresponding coverage-based SRGM is expected to be widely applicable. This paper first conducts a study of selecting the most representative coverage functions among the available coverage functions. Then their performances are empirically evaluated and compared. The result provides a foundation for developing widely applicable coverage-based SRGMs and monitoring the progress of a testing process.