from Amazon
Friday, August 29, 2008
RARP v VORP
BP has two measures that do similar things. One is called VORP, by Keith Woolner, and another is called RARP, by Clay Davenport. They both exist because BP was allowing its analysts to develop their own metrics, which is a good thing. According to BP’s glossary, VORP is “The number of runs contributed beyond what a replacement-level player at the same position would contribute if given the same percentage of team plate appearances” and RARP is “A statistic that compares a hitter’s Equivalent Run total to that of a replacement-level player who makes the same number of outs and plays the same position”.
First, a big thanks to BP for making the data so accessible. And, they are pretty good on name matches, making my life alot easier. There were only some 40 or so names out of 912 that I had to match manually.
The total VORP, as of today, is 4436 runs. And for RARP, it is 4735 runs. This is based on around 154650 PA, which means that per 700 PA, we have this:
VORP: +20.0 runs
RARP: +21.4 runs
As you can see, both have a very similar replacement baseline. Indeed, this is a very common baseline. MGL uses +19.4 runs, and I use (roughly) +19.8 runs.
The question is if either measure shows much difference. This is the 10 guys that VORP likes more than RARP:
diff RARP VORP Name
11.2 42.7 53.9 AUBREY HUFF
10.3 62.7 73.0 LANCE BERKMAN
10.0 51.6 61.6 MATT HOLLIDAY
9.0 39.3 48.3 KEVIN YOUKILIS
8.4 36.0 44.4 DUSTIN PEDROIA
8.4 20.9 29.3 DERREK LEE
7.3 48.8 56.1 ALEX RODRIGUEZ
7.0 18.2 25.2 CRISTIAN GUZMAN
6.7 48.5 55.2 MARK TEIXEIRA
6.7 11.2 17.9 CARLOS ZAMBRANO
And these are the guys that RARP likes more than VORP.
diff RARP VORP Name
-9.0 37.3 28.3 BRIAN GILES
-8.9 25.3 16.4 JACK CUST
-8.0 -3.6 -11.6 BRAD WILKERSON
-7.5 -0.8 -8.3 JACK HANNAHAN
-7.2 3.1 -4.1 JOHN BUCK
-7.1 13.5 6.4 MARK ELLIS
-6.9 -2.0 -8.9 MARK TEAHEN
-6.4 2.2 -4.2 JEFF MATHIS
-6.4 47.4 41.0 JOE MAUER
-5.9 6.7 0.8 JASON VARITEK
Alex Rodriguez is either +1 run ahead of Mauer according to RARP or he is +16 runs ahead of him according to VORP.
Here are the positional totals:
Pos RARP VORP n
1B 660.3 700 53
LF 655.7 625.1 75
CF 585.8 571.6 51
3B 583.4 527.8 55
RF 581.6 483.7 50
2B 548.9 550.6 60
SS 476 477.7 66
C 459 302.1 88
Ot 171.9 189.3 88
P 12.3 8.0 326
We see an enormous gap among catchers and RF. RARP likes catchers by an extra 157 runs, and RF by an almost extra 100 runs.
You will also notice that Carlos Zambrano (the hitter) is on the list. Strangely, all the pitchers as a group are close to zero. The range of VORP goes from +18 Zambrano and +10 Backe to -6 Lohse and Jimenez. For RARP, it’s +7 Zambrano and +4 Owings to -2 Cueto and Lohse. Indeed, when you look at standard deviations, VORP is 50% wider than RARP among pitchers-as-hitters.
I have no editorial comment.