Hey everyone! In our last video we talked about ERA, how it’s calculated, why we use it, and its flaws. In this segment, we will be discussing Fielding Independent Pitching, also known as ‘FIP.’
FIP is a pitching metric that better measures how a pitcher actually performed. What makes FIP different is that it isolates factors a pitcher has more control over and ultimately gives us a better tool for predicting future performance compared to ERA.
FIP Explained
FIP is one of many Defense Independent Pitching Statistics or “DIPS” for short. The main methodology behind FIP is to remove team defense out of the equation and sequencing of hits because a pitcher has little control over what happens once a ball is put in play and the quality of the defense behind them.
If you were trying to analyze how well a particular pitcher threw, you likely wouldn’t consider factors that he can’t control. If he plays for a team with a below-average defense, more hits can get through, and more errors may be made, worsening a pitcher’s stat such as ERA.
Because of this, Fielding Independent Pitching (and DIPS) attempts to isolate and evaluate what the pitcher does have more control over, which is their ability to get strikeouts, limit walks, and home runs.
You may have heard strikeouts, home runs, and walks as the three true outcomes. Understanding a pitcher’s ability to influence the three true outcomes can give us a more accurate indication of their performance.
FIP is calculated using the following equation:
(13*HR + 3*BB – 2*K) / IP + C
We use linear weights to correctly value each outcome, with “C” being a constant which matches the league average FIP to the league average ERA. You can find each year’s league “constant” on fangraphs.com.
While the equation may look complicated, what you need to know is that FIP is meant to look and feel like ERA, which is already familiar—where lower is better. Unlike ERA, which tells us how many runs a pitcher actually gave up, FIP instead tries to calculate what a pitcher’s ERA should have been, based on their ability to influence the 3 true outcomes with league average results on balls in play.
Even though FIP is thought to be more useful in evaluating a pitcher than ERA, it’s not without its flaws either. Mainly, in the same way that pitchers have little control over the outcomes of balls in play, they also have limited control over the environments they play in.
This refers more to ballpark factors, where in one stadium, a pitcher who gives up a fly ball to left center field that goes 379 feet is a home run, whereas in others it might not be. FIP is not park or league adjusted, although other versions account for this.
Summary
FIP is a starting tool that strives to better represent a pitcher’s performance than ERA. It’s proven to be a much better predictor of future ERA than ERA itself and when used correctly it can help evaluate certain components of a pitcher’s game.
You can read more on this topic and find FIP on player pages on FanGraphs, and it is the base metric for its player Wins Above Replacement (fWAR) valuation.
Related Links
FIP | Sabermetrics Library (fangraphs.com)
Major League Leaderboards » 2021 » Pitchers » Dashboard | FanGraphs Baseball
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