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Runs Prevented Rankings I

Over the last couple of months, some comments based on Runs Prevented have helped me to re-evaluate how I present the statistic on the website (and, by extension, on BPMilwaukee Twitter, where I publish the Brewers Daily Pythagorean (or Run Differential, RS / RA) record). Thus, in March I posted a basic explanation of how I use Runs Prevented. Now, I’d like to actually publish periodic rankings of MLB team performance by Runs Prevented.

Explanation: Exploring Runs Prevented

Following a new format for my articles (where possible), the tables will be presented first for those who do not wish to read about the guts.

Table One: 2018 Runs Prevented by MLB, AL / NL, cFIP, and DRA; Ranked by Current AL / NL Runs Prevented

Team (BP) MLB_Prv Lg_Prv cFIP_Prv DRA_Prv
HOU 65 73 15 93
ARI 57 51 30 77
BOS 39 48 20 44
WAS 35 30 20 38
MIL 34 28 4 0
PHI 30 25 7 21
CLE 14 23 16 38
ANA 14 22 -10 12
NYN 14 22 9 26
SLN 27 22 -9 -29
CHN 27 22 -5 -13
COL 25 19 44 72
ATL 18 13 -2 14
DET -7 2 -2 1
TOR -10 -1 -10 -37
PIT 4 -2 -2 7
MIN -10 -3 -7 -8
LAN 0 -5 13 39
SEA -16 -8 -4 13
NYA -3 -8 11 24
OAK -24 -16 -10 3
TEX -26 -17 -6 -60
TBA -25 -17 -17 -7
SFN -16 -22 -11 -27
SDN -20 -26 -10 -22
CIN -27 -33 -6 -32
BAL -51 -43 -10 -36
KCA -57 -49 -24 -67
CHA -56 -49 -34 -106
MIA -50 -55 -24 -34
Average 0 1 0 1

If you cite this table, please link this article and cite Baseball Prospectus and Baseball Reference.

At the team level, Runs Prevented basically expresses the extent to which a club’s pitching staff is better or worse than the league average adjusted for their park factor. Thus, it scales team pitching production to the environment faced by pitchers (both in terms of overall league, and in terms of park). Yet, this is only one way to present the stat; strength of schedule could be included, and different park factors could also be used. I happen to prefer the multi-year factor published on Baseball Reference, but that’s not to say that other metrics are not valid for other presentations of this statistic.

Table Two: DRA Correction of 2018 Runs Prevented for 162 Game Performance


2018 DRA Correction DRA_162 RA_162 DRA_Correction
HOU 344 418 316
ARI 472 573 264
COL 525 727 219
BOS 639 625 171
WAS 561 591 134
CLE 657 714 130
LAN 532 702 105
NYN 654 668 97
PHI 609 591 88
NYA 616 752 68
ANA 702 663 55
ATL 635 640 53
SEA 663 744 29
MIL 710 608 29
PIT 661 694 18
DET 774 771 5
OAK 719 791 -8
CHN 781 640 -19
MIN 787 764 -28
TBA 728 767 -38
SLN 817 612 -66
SDN 750 766 -84
SFN 773 755 -95
TOR 912 776 -104
CIN 813 817 -119
BAL 873 899 -146
MIA 780 860 -154
TEX 1020 862 -176
KCA 996 927 -234
CHA 1167 930 -383
Average 722 722 4

If you cite this table, please link this article and cite Baseball Prospectus and Baseball Reference.

To account for these types of variances, in recent years I have periodically scaled Runs Prevented to Deserved Run Average (DRA) and contextual Fielding Independent Pitching (cFIP) stats. The table above demonstrates 162-game Runs Allowed and “DRA Allowed,” along with an estimate using DRA to correct Runs Prevented. The benefit of using these stats to publish Runs Prevented metrics is that one can attempt to use two predictive metrics to assess teamwide performance. This essentially could help to scale expectations about whether a club’s Runs Prevented performance is sustainable; for example, as Table One showed, the Brewers’ exceptional pitching staff, a top five team by runs prevented, is basically on pace to be an average club over 162 games when assessed by both cFIP and DRA factors. So while there are reasons to think the club could sustain its performance in terms of winning (the bullpen is one of the very best in the league at 3.22 DRA), overall one might expect the club to descend back to an average Runs Prevented performance. (Should this team continue to contend for the playoffs, they could be one particularly strange playoff team, basically driven solely by elite fielding and elite bullpen performances). (Yes, the Brewers fielding performance is very, very good.)

Table Three: Variance of 162 Game Extrapolation for 2018 Runs Prevented

162 Game Pace High Low StDev Average
MLB 234 -234 124 0
AL / NL 263 -213 119 5
cFIP 165 -141 64 -2
DRA 337 -440 167 4

This is not necessarily a knock on the Brewers, however. As the table above shows, extrapolating runs prevented figures over a 162 game demonstrates remarkable variance. There is really a statistical sense in which the baseball could land any which way, meaning that an average pitching staff could be expected to land within a wide range of outcomes the vast majority of seasons. The variance figures above are not necessarily foreign, nor are they solely due to extrapolation (even if extrapolation contributes some of the variance here); in 2017 NL, the average NL club of 0 Runs Prevented demonstrated Standard Deviation of +/- 100 runs, while the average AL club of 1 Run Prevented demonstrated Standard Deviation of +/- 91 runs. (Hence, aces do not exist.) Internal to their own range of MLB, league, cFIP, and DRA Runs Prevented extrapolations over 162 games, each team does not fare much better, with a typical variance of +/- 56 runs. This range should be intuitive when one considers a club like Milwaukee, where the club could indeed finish 124 runs better than average at their current pace, or decline to 2 runs below average at a harsher DRA pace.

Brewers 162 RS RA Wins
NL 4.32 4.25 82
Current -66 95 86
Bats Correction Only -6 95 92
Bats & DRA Corrections -6 29 85
DRA Correction Only -66 29 79

If the Brewers pitching follows their DRA correction course, the offensive troubles of the club will be amplified over the course of the remaining season. Thankfully, the thawed out bats in May are producing runs at a generally average rate, meaning that the club could have a completely different look by the end of the season. Milwaukee’s likely range of Run Differentials is quite well defined even after only 44 games, which places the club in an intriguing position: while the bats provide rather obvious spots for improvement, depending on how the front office views the underlying pitching performances, the pitching staff could be a site for roster improvement as well.


 

Photo Credit: Jennifer Stewart, USA Today Sports Images


References:

Baseball Prospectus. Team Pitching – Standard. CSV retrieved May 17, 2018.
Baseball Reference. Team Standard Pitching [MLB, NL, AL]. CSV Retrieved May 17, 2018.
Baseball Reference. Three Year Park Factors. Retrieved from baseball-reference.com, May 17, 2018.

Stats:

MLB Runs Prevented: Based on MLB RA9 of approximately 4.45, and Three Year Park Factors (Baseball Reference). [(IP/9)*(MLB_RA9 * Park Factor)] – [Actual Team RA]

League Runs Prevented: Based on NL or AL RA9 and Three Year Park Factors. [(IP/9)*(League_RA9 * Park Factor)] – [Actual Team RA]

cFIP Runs Prevented: Based on NL or AL RA9 and Three Year Park Factors, plus each club’s cFIP according to Baseball Prospectus. [(IP/9)*(League_RA9 * Park Factor)] – [(IP/9) * (League RA9 * cFIP/100)]

DRA Runs Prevented: Based on NL or AL RA9 and Three Year Park Factors, plus each club’s DRA according to Baseball Prospectus. [(IP/9)*(League_RA9 * Park Factor)] – [(IP/9) * (DRA)]

162 Game Pace Stats: For DRA and standard RA/G, take either stat and do the following: [RA/G  * 162] or [DRA/G * 162]

DRA Correction: Building on current Runs Prevented, this stat estimates what a club’s final Runs Prevented would be if the remaining games follow DRA. [Current Runs Prevented] + [ (162 Game DRA Pace) * (Percentage of Remaining Games)]

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