I am a huge fan of pitching statistics research. Of all the excellent work being done by public sabermetricians today, I can say that nothing is better than the work being done by Jonathan Judge and the Baseball Prospectus stats team on Deserved Run Average. DRA, for those uninitiated, is a pitching statistic that is on the same scale of RA9, but tries to answer the question of how many runs were deserved to be credited to a pitcher controlling for a variety of outside circumstances: opposing lineups, defense, park, weather, catcher, and umpire, for example.
In its first instantiation, it has proven to have a better predictive value than any other pitching statistic out there.