View Full Version : DIPS-xFIP-ERA comparison

10-01-2007, 02:41 PM
DIPS AND xFIP are both sabermetric ways of looking at how a pitcher performs. In that way they are similar to the traditional baseball statistic known as ERA. Many people would argue that DIPS and xFIP are an improvement upon ERA in that they attempt to take a team's fielding skills out of the equation. It is believed that this results in a truer evaluation of how a pitcher performed.

Since both metrics (DIPS and xFIP) have their backers, I decided to take an average of the two and compare that to ERA. This is how things shook down for Reds' pitchers in 2007. ERA is the traditional ERA. AV-ERA is the average of DIPS and xFIP.

Pitcher ERA Pitcher AV-ERA
Burton 2.51 Bray 3.44
Weather 3.59 Harang 3.68
Harang 3.79 Burton 4.06
Salmon 4.13 Salmon 4.32
Arroyo 4.23 Belisle 4.33
Coutlng 4.39 Weathers4.41
Gosling 4.91 Arroyo 4.55
Shearn 4.96 Stanton 4.56
Belisle 5.32 Majwski 4.57
Bailey 5.76 McBeth 4.58
Coffey 5.82 Coffey 4.68
Stanton 5.93 Coutlng 4.82
McBeth 5.95 Gosling 4.83
Bray 6.28 Guardad 5.23
Saarlos 7.17 Bailey 5.25
Guardad 7.24 Saarlos 5.26
Ramirez 7.71 Shearn 6.13
Majwski 8.22 Ramirez 6.81
Dumatra 15.00 Dumatra 7.24

The sabermetric metrics showed that a handful of pitchers performed worse than their ERA indicates; however, a greater number performed better. It should also be noted that there is a much tighter grouping using DIPS and xFIP, indicating that pitching ability does not vary widely from pitcher to pitcher in most cases.

Above are listed only the pitchers that are likely to perform for the Reds next season. These pitchers threw 1173 innings in 2007 and allowed 643 Earned Runs. If you use the average of the defense-independent metrics and work backwards, these same pitchers should have allowed only 587 Earned Runs in the same 1173 innings. This is a significant difference - 56 runs.

Luck and a team's defensive ability (or lack thereof) probably account for most of this difference. I believe luck tends to even out over 162 games (for the most part), so that leaves team defense.

The combined actual ERA of the pitchers listed above is 4.93. The combined DIPS-xFIP ERA is 4.50. So here is something to be optimistic about for next season. With average luck and with average team defense, the Reds' pitching staff might allow around (4.93-4.50)*162=69 less runs next season. Of course, it is questionable whether the Reds will be a league-average defensive squad in 2008.

Defense-independent metrics show Matt Belisle in a favorable light. And with a year under his belt, look for Homer Bailey to improve. A number of the relievers also look better when viewed in a defense-independent context. Maybe this pitching staff is not as far off as it first seemed.

10-01-2007, 03:22 PM
the team will never have defense with the griffey fossil around, no winning seasons since he has arrived

Jay Bruce
10-01-2007, 03:55 PM
the team will never have defense with the griffey fossil around, no winning seasons since he has arrived

What about 2000, when the Reds won 85 games?

10-01-2007, 11:14 PM
I have been looking for this same information, but I didn't know where to find DIPS. Where do you get it?

I have been harping this for a long time but I'll continue - Matt Belisle is not bad. I know xFIP agrees with me, and from your post it seems like DIPS does too. Take a look at these xFIPs for 2007:

Belisle 4.32
Arroyo 4.76
Carlos Zambrano 4.65
Ted Lilly 4.38
Ben Sheets 4.48 (this was a much worse year for him than normal)

Keep Belisle in the rotation. I think Reds fans will be pleasantly surprised by his performance in 08.

Edit: You are right about the defense, it is really bad. And Gary Majewski having a respectable xFIP blows my mind, it is almost half of his real ERA.

Javy Pornstache
10-02-2007, 01:38 AM
Good thread, texasdave. I agree with McGavin as well, I am not sure why many are quick to run Belisle off. Many of the surface numbers aren't pretty for him, and I know I've been concerned with his enormous opponent batting average against (worst in the NL for a good chunk of the year in that category), but know he had a BABIP on the high side, and his peripheral numbers have consistently been strong, solid K/9 and BB/9 rates. Not saying he's a #3 starter, but his stuff looks to me like a guy you don't want to run off when you're a team who has three huge holes in your rotation going into next year. One of those three can easily be plugged right here.