Paper author here. We did a follow up study and found that the mutation score is, in fact, correlated with the suite's ability to detect real faults, at least

Paper author here. We did a follow up study and found that the mutation score is, in fact, correlated with the suite's ability to detect real faults, at least for the programs we studied. That paper is also on my website: "Are Mutants a Valid Substitute for Real Faults in Software Testing?"