More on the LIPS/FIP discrepancy by Derek Carty June 17, 2009 On Monday, I examined two ERA estimators, FIP and LIPS, and discussed the pitchers who have been most undervalued or overvalued by FIP so far this year. For my discussion on the shortcomings of FIP, be sure to check out that article. For an explanation of LIPS, check out David Gassko’s primer from yesterday. As a couple of readers pointed out, while almost all of the players on my list from Monday had abnormally high or low HR/FB rates (which is to be expected since FIP doesn’t normalize HR/FB), there were a few pitchers who saw a big disparity between FIP and LIPS yet had completely normal HR/FB rates. How could this be? The answer is that while the biggest difference between LIPS and FIP is the fact that LIPS normalizes HR/FB, LIPS also takes into account a few other things that FIP does not. So today, I’m going to look at a few of the starting pitchers with at least 40 innings pitched and at least a 0.50 LIPS/FIP difference and examine why this difference exists. 2009 – SP with largest differences between LIPS and FIP +-------------+------------+----+----+-------+------+------+----------+----------+-------+ | LAST | FIRST | G | GS | IP | ERA | FIP | LIPS ERA | LIPS-FIP | HR/FB | +-------------+------------+----+----+-------+------+------+----------+----------+-------+ | Hammel | Jason A | 12 | 9 | 54.0 | 4.33 | 3.99 | 4.94 | 0.95 | 11 | | Cook | Aaron | 13 | 13 | 76.0 | 4.26 | 4.70 | 5.41 | 0.71 | 15 | | Halladay | Roy | 14 | 14 | 103.0 | 2.53 | 2.62 | 3.25 | 0.63 | 10 | | Beckett | Josh | 12 | 12 | 76.3 | 3.77 | 3.53 | 4.14 | 0.61 | 10 | | Buehrle | Mark | 12 | 12 | 80.7 | 3.24 | 4.15 | 4.76 | 0.61 | 11 | | Cabrera | Daniel A | 9 | 8 | 40.0 | 5.85 | 6.36 | 6.95 | 0.59 | 10 | | Hampton | Mike | 12 | 12 | 67.0 | 4.70 | 4.64 | 5.22 | 0.58 | 13 | | Floyd | Gavin C | 13 | 13 | 82.0 | 4.94 | 3.79 | 4.29 | 0.50 | 10 | +-------------+------------+----+----+-------+------+------+----------+----------+-------+ | Slowey | Kevin | 13 | 13 | 78.7 | 4.23 | 4.09 | 3.57 | -0.52 | 11 | | Young | Chris | 13 | 13 | 73.7 | 4.76 | 5.13 | 4.16 | -0.97 | 11 | +-------------+------------+----+----+-------+------+------+----------+----------+-------+ Note: For continuity’s sake, these numbers haven’t been update since Monday’s article. Jason Hammel – Worse than FIP indicates Hammel has the largest negative difference between FIP and LIPS so far in 2009, and I can see two primary reasons for this. 1) Hammel pitches for the Rockies and, therefore, in Coors Field. As Coors inflates run scoring by 9.3 percent, this will have a large impact on Hammel’s numbers that FIP simply ignores. 2) Hammel’s infield fly ball rate (2.7 percent) is lower than league average (3.9 percent). Aaron Cook – Worse than FIP indicates . Cook is interesting in that his LIPS ERA is worse than his FIP, yet his FIP is being driven by an abnormal 15 percent HR/FB. If you were to normalize the HR/FB and apply the FIP formula, the difference would actually be even larger (his xFIP is 4.31, a 1.10 difference from LIPS). Like Jason Hammel, being a Rockie has a lot to do with this. The run-scoring in Coors obviously has a big effect as these are the top two guys on the list. In addition, Cook’s infield fly ball rate is a measly 0.4 percent compared to a league average of 3.9 percent. As he allows a ton of balls in play to begin with, the effect is amplified. Roy Halladay – Worse than FIP indicates Halladay’s difference is being driven by the same two factors as Cook. 1) The Rogers Centre inflates run scoring by 3.1 percent. 2) His infield fly ball rate (2.7 percent) is lower than league average (3.9 percent). Mark Buehrle and Gavin Floyd – Worse than FIP indicates Both induce fewer infield flies than average and both call hitter-friendly U.S. Cellular home. Chris Young – Better than FIP indicates Chris Young has the most extreme LIPS/FIP difference of any pitcher in baseball this year, whether under or overvalued. Three factors are driving this: 1) PETCO reduces run scoring by 7.7 percent. 2) He induces more than twice as many infield flies (7.7 percent) than league average (3.9 percent). 3) He hits fewer batters (0.24 per 9) than league average (0.35 per 9) Kevin Slowey – Better than FIP indicates Slowey’s difference is being driven primarily by two factors. 1) He induces a lot of infield flies (6.5 percent), and because his strikeout ability is merely average-ish, the raw number of infield flies is pretty high. 2) His line drive rate (21 percent) is higher than league average (19.1 percent). Because he’s letting up too many line drives, he isn’t inducing as many groundballs, pop-ups, and fly balls as he should be, all of which do less damage than line drives. A Hardball Times Updateby RJ McDanielGoodbye for now.