FIP, or Fielding Independent Pitching, is based on the idea that pitchers are only in control of the “3 true outcomes” of a plate appearance: Strikeouts, Home Runs, and Free Passes (HBP and BB’s). Everything else relies on defense which is largely beyond the pitcher’s control. FIP is scaled, through the use of a constant, to a league’s ERA.
The formula to derive FIP is:
FIP = ((13*HR)+(3*(BB+HBP))-(2*K))/IP + constantand the formula for the deriving the constant is similar:
FIP Constant = lgERA – (((13*lgHR)+(3*(lgBB+lgHBP))-(2*lgK))/lgIP)We’re going to make a quick table to calculate the FIPConstant for each league year that we’ll reference when calculating FIP for each player stint. Happily, the game gives us league ERA in the league_history_pitching_stats table, so we’ve been spared a step. Because I am, apparently, not very good with the order of operations and parentheses, I have spent the last hour pulling my hair out trying to get a FIP Constant that looks reasonable. In an attempt to save some of my last remaining hairs, I made a very inelegant table. Behold my genius:
DROP TABLE IF EXISTS FIPConstant;
CREATE TABLE IF NOT EXISTS FIPConstant AS
SELECT
lhps_id
, year
, league_id
, level_id
, hra
, bb
, hp
, k
, @HRAdj := 13*hra AS Adjusted_HR
, @BBAdj := 3*bb AS Adjusted_BB
, @HPAdj := 3*hp AS Adjusted_HP
, @KAdj := 2*k AS Adjusted_K
, @InnPitch := ((ip*3)+ipf)/3 AS InnPitch
, era
, era - ((@HRAdj+@BBAdj+@HPAdj-@KAdj)/@InnPitch) AS FIPConstant
FROM league_history_pitching_stats;On the CalcPitching table, we’re adding FIP and disregarding left/right splits for the moment. Our table script now looks like this:
DROP TABLE IF EXISTS CalcPitching;
CREATE TABLE IF NOT EXISTS CalcPitching AS
SELECT
i.player_id
, i.year
, i.stint
, i.team_id
, i.league_id
, split_id
, i.ip
, i.ab
, i.tb
, i.ha
, i.k
, i.bf
, i.rs
, i.bb
, i.r
, i.er
, i.gb
, i.fb
, i.pi
, i.ipf
, i.g
, i.gs
, i.w
, i.l
, i.s
, i.sa
, i.da
, i.sh
, i.sf
, i.ta
, i.hra
, i.bk
, i.ci
, i.iw
, i.wp
, i.hp
, i.gf
, i.dp
, i.qs
, i.svo
, i.bs
, i.ra
, i.cg
, i.sho
, i.sb
, i.cs
, i.hld
, i.ir
, i.irs
, i.wpa
, i.li
, i.outs
, i.war
, @InnPitch := ((3*ip)+ipf)/3 AS InnPitch
, round((9*i.k)/@InnPitch,1) AS 'k9'
, round((9*i.bb)/@InnPitch,1) AS 'bb9'
, round((9*i.hra)/@InnPitch,1) AS 'HR9'
, round((i.bb+i.ha)/@InnPitch,2) AS WHIP
, round(i.k/i.bb,2) AS 'K/BB'
, i.gb/i.fb AS 'gb/fb'
, round((i.ha-i.hra)/(i.ab-i.k-i.hra-i.sh+i.sf),3) AS BABIP
, round(i.er/@InnPitch,2) AS ERA
, round(((13*i.hra)+(3*(i.bb+i.hp))-(2*i.k))/@InnPitch+f.FIPConstant,2) AS fip
FROM players_career_pitching_stats AS i
INNER JOIN FIPConstant AS f ON i.year=f.year AND i.league_id=f.league_id
WHERE i.split_id=1;So, how did it go? Not great. I took a random sample from my database and compared it to the game’s generated stats. I wanted my FIP calculations to be within .05 of the game’s.
While most were in the medium range, it seems that there’s something different in the way the game calculates FIP. Our numbers are close enough that it can’t be a major difference. I’m going to follow a hunch and guess that it’s Hit By Pitch. I will remove HBP as a factor in both the FIPConstant and FIP calculations and see what that does to our results.
I got about a third of the way through the revised calcs when I noticed a problem with the FIPConstant table. This table pulls data from the league_history_pitching_stats table. The problem is there. You see, as I mentioned in the table setup posts and then promptly forgot about, there are a couple of columns in the league_history tables that attempt to distinguish between subleagues but do not give any indication of which is which. (They are the team_id and game_id columns.) What this does create two records for each league (one for each subleague) with different totals but no way to identify the subleague being referenced. This is no good.
My new hunch is that HBP is not the issue. The formula is probably fine, I will just have to change the FIPConstant table to sum data from players_career_pitching_stats. I’m going to publish this post as a testament to my naiveté and get to work on the revised table.