Fielding Player Won-Lost Records vs. Ultimate Zone Rating
Conceptual Difference between UZR and Fielding Player Won-Lost Records
Basic Fielding: Outs vs. Hits on Balls-in-PlayUZR is described in great detail on Fangraphs' website here. The basic concept is that UZR calculates a probability of a ball-in-play being converted into an out, based on the location of the ball, how hard it's hit, the handedness of the batter, the ground-ball tendencies of the pitcher, and various other things. Fielders are then given credit or blame over and above this said probability, so, for example, for a ball-in-play that had a 75% chance of being an out, if the ball becomes a hit, the responsible fielder(s) are debited with -0.75 plays not made (0 - 0.75); if the same ball-in-play became an out, the responsible fielder is credited with 0.25 plays made (1 - 0.75). Plays are then converted to runs based on the average run value of balls-in-play based on the location, et al.
Hits vs. Fielding ErrorsUZR treats errors somewhat differently from hits. According to the UZR Primer at Fangraphs, errors are assumed to have been easy plays with high probabilities of being outs. Hence, UZR penalizes fielders more heavily for errors than for hits on balls-in-play.
Additional Components of FieldingIn addition to the basic "range runs" and "error runs" described above, UZR also calculates run values for fielders based on their ability to turn double plays (infielders) and their ability to control baserunner advancement (outfielders). Fangraphs reports these values separate from the UZR estimates based purely on whether balls-in-play are converted to outs or not, but combines them into a single final number which it reports as a player's total UZR.
Raw ResultsFor this article, I compare two measures of UZR and (context-neutral, teammate-adjusted) Net Fielding wins (eWins minus eLosses): total UZR runs vs. total Net Fielding wins, and (Range + Error) UZR runs vs. net Component 5 Fielding wins. For outfielders, I also calculate a third measure of Net Fielding wins which excludes Component 6 - since UZR has no counterpart - which I compare to total UZR runs. To be clear, on this last measure, I exclude Component 6 only to allow for an apples-to-apples comparison to UZR. The fact that my Fielding records include this measure of the exact value of the hits allowed by fielders while UZR relies only on average hit values across similar plays is, in my opinion, a clear advantage of Fielding Player won-lost records over UZR as an overall measure of player fielding.
UZR Net Fielding Runs (per 1,000 innings) | Net Fielding eWins (per 1,000 innings) | ||||||||||
Total UZR |
UZR, Range+Error |
Total Fielding eWins |
Component 5 eWins |
Total eWins, excl. Comp. 6 | |||||||
Position | No. of Players | Mean | Std. Dev. |
Mean | Std. Dev. |
Mean | Std. Dev. |
Mean | Std. Dev. |
Mean | Std. Dev. |
---|---|---|---|---|---|---|---|---|---|---|---|
1B | 36 | -0.12 | 4.31 | -0.09 | 4.24 | 0.008 | 0.209 | 0.013 | 0.181 |
||
2B | 41 | 0.12 | 4.66 | -0.05 | 4.46 | 0.001 | 0.279 | -0.014 | 0.254 |
||
3B | 49 | 0.80 | 6.24 | 0.77 | 6.08 | 0.028 | 0.341 | 0.018 | 0.332 |
||
SS | 45 | 0.54 | 4.90 | 0.43 | 4.61 | 0.044 | 0.261 | 0.041 | 0.197 |
||
LF | 30 | -0.46 | 6.82 | -0.21 | 6.36 | -0.002 | 0.340 | -0.002 | 0.280 | -0.007 | 0.307 |
CF | 49 | 0.52 | 6.29 | 0.27 | 6.25 | 0.038 | 0.373 | 0.015 | 0.262 | 0.032 | 0.357 |
RF | 38 | 0.53 | 6.38 | 0.23 | 5.78 | 0.049 | 0.405 | 0.018 | 0.298 | 0.052 | 0.393 |
Why is the Spread on Player Fielding Wins lower than Defensive Runs?I believe that the spread on my net fielding wins is less than the spread of UZR (and other fielding measures) because I assign more credit on balls-in-play to pitchers, whereas stand-alone fielding measures implicitly assign all of the credit on balls-in-play to fielders, since that's all that they are measuring.
Putting Things on the Same ScaleIn order to really compare UZR and what I'll start calling NFW (net fielding wins), it is necessary to put them on the same scale. To do this, I created "z-scores" associated with both statistics. The basic formula for a z-score of variable x is (x - m) / s, where m is the mean of the statistic and s is the standard deviation. I calculated z-scores for each player for UZR and net fielding wins using a value of m equal to zero (since both of these statistics are constructed to be relative to league average by construction) and the standard deviations from the above table.
UZR v. NFW | |||
Position | Total | Comp. 5 only | excl. Comp. 6 |
---|---|---|---|
1B | 0.864 | 0.886 | |
2B | 0.812 | 0.826 | |
3B | 0.869 | 0.873 | |
SS | 0.778 | 0.793 | |
LF | 0.730 | 0.721 | 0.715 |
CF | 0.558 | 0.494 | 0.519 |
RF | 0.724 | 0.698 | 0.729 |
Position-by-Position Analysis
First BaseFor the 36 players evaluated here, the average difference in z-scores between UZR and NFW (NFW minus UZR) is 0.064. The average absolute difference in z-scores between UZR and NFW is 0.451. For Component 5 only, the average difference is 0.094 and the average absolute difference is 0.395.
Fielding Z-Score | |||||
UZR (Fangraphs) | NFW (Thress) | ||||
Player | Innings | Total | Range+Err | Total | Comp. 5 |
---|---|---|---|---|---|
Mike Jacobs | 3,236.1 |
-2.099 | -2.083 |
-0.890 | -1.295 |
Scott Hatteberg | 4,777.0 |
-0.413 | -0.400 |
0.607 | 0.800 |
Second BaseFor the 41 players evaluated here, the average difference in z-scores between UZR and NFW (NFW minus UZR) is -0.023. The average absolute difference in z-scores between UZR and NFW is 0.480. For Component 5 only, the corresponding numbers are -0.045 and 0.469, respectively.
Fielding Z-Score | |||||
UZR (Fangraphs) | NFW (Thress) | ||||
Player | Innings | Total | Range+Err | Total | Comp. 5 |
---|---|---|---|---|---|
Brandon Phillips | 10,043.1 |
1.313 | 1.432 |
-0.389 | -0.186 |
Brian Roberts | 9,607.2 |
0.532 | 0.607 |
-0.600 | -0.346 |
Freddy Sanchez | 5,413.0 |
0.666 | 0.568 |
-0.146 | -0.458 |
Rickie Weeks | 7,703.2 |
-1.093 | -1.055 |
-2.196 | -2.260 |
Skip Schumaker | 3,182.1 |
-1.997 | -2.215 |
-0.725 | -1.261 |
Third BaseFor the 49 players evaluated here, the average difference in z-scores between UZR and NFW (NFW minus UZR) is -0.047. The average absolute difference in z-scores between UZR and NFW is 0.409. Looking only at Component 5, the differences are -0.071 and 0.422, respectively.
Fielding Z-Score | |||||
UZR (Fangraphs) | NFW (Thress) | ||||
Player | Innings | Total | Range+Err | Total | Comp. 5 |
---|---|---|---|---|---|
David Bell | 4,456.0 |
0.960 | 0.938 |
-0.171 | 0.018 |
Eric Chavez | 6,700.1 |
0.624 | 0.633 |
1.645 | 1.499 |
Geoff Blum | 3,256.0 |
1.157 | 1.223 |
0.144 | 0.333 |
Mike Lowell | 8,048.0 |
0.163 | 0.121 |
1.337 | 0.953 |
Vinny Castilla | 4,308.1 |
0.275 | 0.206 |
1.053 | 1.248 |
ShortstopFor the 45 players evaluated here, the average difference in z-scores between UZR and NFW (NFW minus UZR) is 0.057. The average absolute difference in z-scores between UZR and NFW is 0.590. For Component 5, the corresponding numbers are 0.112 and 0.540.
Fielding Z-Score | |||||
UZR (Fangraphs) | NFW (Thress) | ||||
Player | Innings | Total | Range+Err | Total | Comp. 5 |
---|---|---|---|---|---|
Angel Berroa | 5,673.1 |
-1.163 | -1.442 |
-0.035 | -0.769 |
Asdrubal Cabrera | 4,380.0 |
-1.403 | -1.610 |
-0.129 | -0.520 |
Cliff Pennington | 3,971.2 |
-0.242 | -0.568 |
1.192 | 0.726 |
Clint Barmes | 4,907.0 |
1.336 | -1.172 |
1.687 | 2.242 |
J.J. Hardy | 8,115.0 |
1.621 | 1.770 |
0.505 | 0.943 |
Khalil Greene | 5,941.2 |
-0.498 | -0.588 |
0.199 | 0.687 |
Marco Scutaro | 5,734.2 |
-0.449 | -0.378 |
0.317 | 0.776 |
Michael Young | 6,737.1 |
-1.707 | -1.546 |
-1.078 | -0.415 |
Troy Tulowitzki | 6,430.0 |
0.867 | 0.658 |
1.923 | 1.519 |
Left FieldFor the 30 players evaluated here, the average difference in z-scores between UZR and NFW (NFW minus UZR) is 0.063. The average absolute difference in z-scores between UZR and NFW is 0.575. For Component 5, the corresponding numbers are 0.025 and 0.580, respectively. For total Player won-lost records, excluding Component 6, the numbers are 0.045 and 0.603.
Fielding Z-Score | ||||||
UZR (Fangraphs) | NFW (Thress) | |||||
Player | Innings | Total | Range+Err | Total | (excl Comp. 6) | Comp. 5 only |
---|---|---|---|---|---|---|
Alfonso Soriano | 7,680.2 |
1.375 | 1.060 |
0.482 | 0.456 | -0.050 |
Carlos Lee | 10,568.1 |
-0.222 | -0.134 |
-1.431 | -1.333 | -1.156 |
Cliff Floyd | 3,757.0 |
-0.402 | -0.690 |
0.607 | 0.832 | 0.603 |
Jay Payton | 3,572.2 |
0.094 | -0.026 |
1.108 | 0.872 | 0.959 |
Moises Alou | 4,007.2 |
1.003 | 1.235 |
-1.225 | -1.143 | -0.859 |
Randy Winn | 3,084.0 |
0.528 | 0.713 |
1.419 | 1.235 | 1.763 |
Carlos Lee | Moises Alou | |||||
Season | Innings | UZR | NFW | Innings | UZR | NFW |
---|---|---|---|---|---|---|
2003 | 1,328.2 | 0.86 | -0.01 |
1,219.0 | 1.43 | -0.73 |
2004 | 1,277.2 | 1.68 | 0.81 |
1,338.1 | 2.00 | -0.93 |
2005 | 1,404.0 | -0.25 | -0.36 |
576.0 | 0.61 | 0.34 |
2006 | 1,259.1 | -1.69 | -2.19 |
79.0 | -3.71 | -0.95 |
2007 | 1,369.1 | -0.32 | -1.25 |
703.0 | -0.65 | -3.15 |
2008 | 915.1 | 0.02 | -3.25 |
92.1 | -0.48 | -8.27 |
2009 | 1,272.1 | -1.08 | -2.57 |
|||
2010 | 1,096.1 | -2.37 | -4.18 |
|||
2011 | 645.1 | 1.95 | 2.03 |
Right FieldFor the 38 players evaluated here, the average difference in z-scores between UZR and NFW (NFW minus UZR) is 0.038. The average absolute difference in z-scores between UZR and NFW is 0.586. For Component 5, the corresponding numbers are 0.022 and 0.635, respectively. For total Player won-lost records, excluding Component 6, the numbers are 0.048 and 0.587.
Fielding Z-Score | ||||||
UZR (Fangraphs) | NFW (Thress) | |||||
Player | Innings | Total | Range+Err | Total | (excl Comp. 6) | Comp. 5 only |
---|---|---|---|---|---|---|
Gary Sheffield | 3,925 |
-1.478 | -1.566 |
-0.226 | -0.369 | 0.068 |
J.D. Drew | 7,805.1 |
0.922 | 1.393 |
0.000 | -0.082 | 0.324 |
Jason Heyward | 3,524.1 |
1.708 | 2.166 |
0.185 | 0.111 | 0.850 |
Jeremy Hermida | 3,745 |
-0.360 | -0.180 |
0.950 | 0.509 | 0.466 |
Jose Bautista | 3,450.2 |
-0.354 | -1.280 |
1.041 | 1.169 | -0.685 |
Kosuke Fukudome | 3,273.2 |
-0.043 | -0.138 |
1.152 | 1.161 | 1.240 |
Mike Cuddyer | 6,064 |
-0.724 | -1.222 |
-1.144 | -1.129 | -2.458 |
Randy Winn | 3,622.1 |
1.874 | 2.027 |
0.631 | 0.615 | 0.948 |
Trot Nixon | 3,924 |
1.019 | 1.129 |
-0.694 | -0.646 | -0.633 |
Xavier Nady | 3,579.1 |
-0.473 | -0.145 |
-1.409 | -1.476 | -1.176 |
Position | eWins | eLoss | Win Pct | Net Wins |
---|---|---|---|---|
3B | 1.8 | 1.3 | 0.582 | 0.5 |
LF | 0.4 | 0.2 | 0.607 | 0.1 |
CF | 1.2 | 0.9 | 0.576 | 0.3 |
RF | 10.3 | 7.3 | 0.584 | 3.0 |
Total | 13.6 | 9.7 | 0.584 | 3.9 |
Center FieldFor the 49 players evaluated here, the average difference in z-scores between UZR and NFW (NFW minus UZR) is 0.018. The average absolute difference in z-scores between UZR and NFW is 0.747. For Component 5, the corresponding numbers are 0.015 and 0.774, respectively. For total Player won-lost records, excluding Component 6, the numbers are 0.007 and 0.767.
Fielding Z-Score | ||||||
UZR (Fangraphs) | NFW (Thress) | |||||
Player | Innings | Total | Range+Err | Total | (excl Comp. 6) | Comp. 5 only |
---|---|---|---|---|---|---|
Adam Jones | 6,371.1 |
-0.487 | -1.030 |
1.110 | 1.086 | -0.272 |
Andruw Jones | 7,327.0 |
2.223 | 1.894 |
0.340 | 0.250 | 0.049 |
B.J. Upton | 7,024.2 |
0.421 | 0.080 |
1.420 | 1.652 | 1.347 |
Denard Span | 3,712.1 |
0.617 | 0.953 |
-1.638 | -1.632 | -1.607 |
Drew Stubbs | 4,034.2 |
0.418 | -0.147 |
0.976 | 0.754 | 1.038 |
Endy Chavez | 3,200.0 |
0.731 | 0.040 |
2.167 | 2.024 | 1.141 |
Franklin Gutierrez | 3,875.1 |
1.995 | 1.925 |
2.344 | 2.213 | 3.078 |
Jacoby Ellsbury | 4,030.2 |
0.746 | 1.207 |
-1.579 | -1.683 | -1.635 |
Johnny Damon | 5,524.0 |
-1.287 | -0.658 |
-2.027 | -1.992 | -1.939 |
Josh Hamilton | 3,148.1 |
-1.132 | -1.073 |
-0.010 | 0.068 | 0.173 |
Juan Pierre | 7,316.1 |
0.387 | 1.079 |
-1.418 | -1.494 | -0.794 |
Ken Griffey, Jr. | 3,198.0 |
-3.278 | -3.269 |
-2.139 | -1.990 | -2.316 |
Mark Kotsay | 5,805.1 |
-0.225 | -0.433 |
0.733 | 0.787 | 0.332 |
Matt Kemp | 6,025.0 |
-1.170 | -1.371 |
0.176 | 0.320 | -0.037 |
Michael Bourn | 6,280.1 |
1.307 | 1.096 |
0.376 | 0.221 | -0.147 |
Rick Ankiel | 3,063.2 |
-0.306 | -0.789 |
0.563 | 0.700 | -0.003 |
Rocco Baldelli | 3,332.0 |
0.086 | -0.663 |
1.020 | 1.153 | -0.350 |
Scott Podsednik | 3,326.1 |
-0.765 | -0.669 |
0.988 | 1.184 | 1.507 |
Sensitivity of UZR to Data SourceIn a separate article, I explain how I use location data in calculating Fielding won-lost records and defend my decision not to use this data directly even for those seasons where Retrosheet provides location data. In that article, I cite two studies that were reported on the Internet that looked at differences in UZR calculated using different source data.
Simplified UZR | |||
Player | BIS | STATS | Difference |
---|---|---|---|
Andruw Jones | +19 | -2 | 21 |
Carlos Beltran | +9 | +14 | 5 |
Jim Edmonds | +8 | -2 | 10 |
Johnny Damon | -6 | 0 | 6 |
Juan Pierre | -1 | -1 | 0 |
Mark Kotsay | +1 | -19 | 20 |
Marquis Grissom | -18 | -6 | 12 |
Mike Cameron | +28 | +21 | 7 |
Vernon Wells | -6 | +6 | 12 |
Correlation | 0.522 | ||
Std. Deviation | 6.87 | ||
Median | 10 |
UZR vs. Net Fielding wins | bUZR vs. sUZR | |
---|---|---|
Std. Deviation of Difference | 5.5 | 6.0 |
Median Difference | 3.5 | 4.0 |
Difference > 4 | 41% | 50% |
Difference > 10 | 6% | 10% |
ConclusionsOverall, I'm quite pleased with the results here. The total correlation across all seven positions (288 players) investigated here, between UZR and my Fielding won-lost records - expressed in terms of z-scores - was 0.745. The z-scores associated with these two systems differed by more than 1 in 36 cases (12.5%).