At Baseball Prospectus, Colin Wyers explains why the site is abandoning its ERA estimator SIERA and details some of the failures of that stat and xFIP compared to FIP and plain-old ERA. It’s a dense read, but worth the effort. It’s a good reminder that all the best efforts to assess baseball teams and players are always works in progress. It’s fun — and valuable, in my opinion — to stay up on the latest thinking, but if you want to cite any one stat as gospel, you should remember that there’s a pretty good chance it’ll go out of vogue within a couple of years.