The catch-all stat that people use to evaluate starting pitchers is ERA, ERA is an incredibly poor way to evaluate a pitcher. ERA makes us think that we are answering the most import question about a pitcher, how many runs were you responsible for? The issues are in the calculations of how you get to that ERA, you don’t count runs that scored because of an error, that seems fair right. What decides if there is an error or not, an official scorer and official scorers do not hand out errors consistently, meaning that the same botched play might be scored an error one day and a hit another. Second, why are runs that are given up due to a sub-par fielder at a position? You’re going to give up fewer runs with Billy Hamilton patrolling your outfield than Daniel Palka, but ERA doesn’t care. In other words, the goal of ERA is perfect but the execution is horrible.
Also, because ERA is highly dependent on non-pitcher factors like defense, umpiring, the scorer, luck, sequencing, etc, it is also not highly predictive of future performance because those factors are not part of the pitcher’s talent level, and therefore, do not often travel with him from season to season. If you are a person who always will look only at ERA because that’s the way its always been done, that’s okay, I guess. You could use a statistic called ERA -. It’s still not a perfect statistic, but it does make it easier to compare pitchers from different time periods and parks, but it contains the same general flaws of standard ERA. ERA – works similar to how OPS+ or wRC+ work for batters, 100 is still average, but the lower the better. If a batter has a 113 OPS+ he is 13 percent better than average. If a pitcher has an 87 ERA- he is 13 percent better than average.
You know what fixes all those problems, FIP. Fielder Independent Pitching, or FIP, is just as it sounds. It credits or debits a pitcher with only what the pitcher can control, or do not depend on luck. Strikeouts, walks, hit batters, and home runs allowed are what pitchers can control. Pitchers can’t control the official scorer, cant overcome the left fielder that can’t get to that gapper because he’s slow or tripped, or because Byron Buxton accidentally made contact with a ball and beat out a slow-footed third baseman’s throw.
Using FIP is extremely easy because it’s designed to look exactly like ERA. This means that you can read and use FIP exactly as you would typically use ERA. If a pitcher has a 3.15 FIP, that’s just like saying they have a 3.15 ERA as far as making comparisons among players is concerned. You don’t have to learn a new scale to interpret a player’s FIP. FIP does a better job of predicting the future than measuring the present, as there can be a lot of fluctuation in small samples. It is less effective in describing a pitcher’s single-game performance and is more appropriate in a season’s worth of innings.
FIP is not league or park-adjusted meaning that pitchers in good pitcher’s parks will have consistently lower FIPs and pitchers who pitch during eras of lower run scoring will have consistently lower FIPs. To control for both of those factors, there is FIP-, which is a park and league adjusted version of the statistic. Again, FIP- works just like ERA -with 100 being average and anything below is that percent above average.
Thanks as always for reading and we will be running these pieces all week for what we are calling advanced stat week. Let us know what you would like to see me tackle or if you have any questions. You can ask or just follow us on twitter @SidedSox, and follow us on Facebook. You can also email us at SoxSided@Gmail.com.