The definition of quality metrics to estimate the mutation operator effectiveness can help us identify the most valuable mutation operators and, eventually, a subset of operators providing a similar performance than the whole set.
The Coverage-Based Quality Metric aims to value mutation operators depending on their usefulness to refine a test suite. The novelty of this quality metric is that it tackles the coverage of the test suite, as not all the mutants are executed by all the test cases. This metric works under the following two assumptions:
Mutants killed by few of the test cases that reach them should be more valuable than those mutants killed by many of the test cases that reach them.
Mutants killed by test cases that kill only few of the mutants reached by them should be more valuable than those mutants killed by test cases that kill many of the mutants reached by them.