Monday, September 01, 2003

Evolution

Welcome back, Baseball Crowd. Or should you be welcoming me back?

Here is a brief review of my experiences with On-Base Percentage (OBP):
- Read Baseball Prospectus for a couple of years.
- Read Moneyball.
- Built my very successful fantasy baseball team around OBP.
- Invented BAP.
- Compared BAP to OBP and SLG in game analysis, only to find out that OBP lagged behind.
- Compared BAP to OPS in game analysis, only to find that OBP was dragging down the OPS scores.
- Compared the run and rbi totals of Richie Sexson to Bobby Abreu, and came to the conclusion that SLG may also be a better barometer of run production than OBP.

Which brings me to this weekend. Got some emails defending Abreu, with folks throwing out alternative reasons why Sexson may have had more runs and rbi than him, and no emails considering my theory either conclusive or a revelation, which I've greedily come to expect since that truly weird BAP experience. I realized I had more work to do.

So this is what I did: First, I tried to find players that were more comparable than Sexson and Abreu. I decided to take players with the exact same OPS scores, and a similar number of at bats. I found five such pairings in the National League.

Then I decided to compare each pair of players' runs, RBIs, percentage of team runs, percentage of team RBIs, and those two percentages added together. All of these stats are obviously related. The general baseball public loves runs and RBIs. Statheads generally hate both stats, because they are largely a function of the team that a player has around them. The problem with this though, is that anyone who's ever watched a baseball game knows that in the course of a game, the most important acts are the runs that are scoring, and the plays that are causing, or preventing, a run from scoring.

Run and RBI totals will always be depressed for a player on a low scoring team. However, looking at a player's percentages of his team's runs and RBI totals will always be depressed for a player on a high scoring team. Because many people on his team are producing runs, the player on the high scoring team can never gain the kind of percentage that a player can on a low scoring team. When virtually no one is producing at a high level, it's easy to be a big part of a team's run and RBI percentage.

Taken separately - Run and RBI totals, and the percentages of team totals - none of the stats mean much. But taken together, they show a lot. If one player has more runs and RBIs than another player, AND a higher percentage of his own team's runs and RBIs than the other player, it's pretty safe to say that player A is doing his job better than player B.

So with my five pairs of players with the exact same OPS and comparable plate appearance numbers, I went into this thinking that if OBP and SLG were equal, then run scores would go to the players with an OBP advantage, RBI scores would go to the Sluggers, and the two percentages added together would be split.

A few definitions before we start. PA is plate appearances, R % is percentage of team' runs total, RBI % is percentage of team's RBI total, and R+RBI % is the R % + RBI%.

And away we go!


Chipper Jones vs. Preston Wilson - OPS .898
PA - CJ 548, PW 573
OBP - CJ .394, PW .348
SLG - CJ .504, PW .649

Runs - CJ 85, PW 84
R % - CJ .109, PW .116
RBI - CJ 90, PW 126
RBI % - CJ .120, PW .182
R-RBI% - CJ .229, PW .298

The man with the higher OBP (Jones) has 25 fewer plate appearances, and has scored one more run. The man with the higher SLG (Wilson) has scored a higher percentage of his team's runs, has more RBIs, a higher RBI %, and a higher R+RBI %. Advantage - Slugging.


Mark Loretta vs. Moises Alou - OPS .823
PA - ML 540, MA 535
OBP - ML .381, MA .354
SLG - ML .442, MA .469

Runs - ML 63, MA 67
R % - ML .112, MA .114
RBI - ML 62, MA 79
RBI % - ML .116, MA .141
R+RBI % - ML .228, MA .255

The man with the higher OBP(Loretta) has five more plate appearances. The man with the higher SLG (Alou) leads in every other category. Advantage - SLG.


Wes Helms vs. Mark Grudzielanek - OPS .765
PA - WH 425, MG 430
OBP - WH .319, MG .361
SLG - WH .446, MG .404

Runs - WH 46, MG 61
R % - WH .076, MG .104
RBI - WH 58, MG 22
RBI % - WH .099, MG .039
R+RBI % - WH .175 , MG .143

The man with the higher OBP (Grudzielanek) has five more plate appearances, and has the higher run total and higher R %. The man with the higher SLG (Helms) has more RBI, the higher RBI %, and the higher R+RBI %. Advantage - SLG.


Juan Encarnacion vs. Sean Casey - OPS .749
PA - JE 545, SC 543
OBP - JE .312, SC .347
SLG - JE .438, SC .402

Runs - JE 66, SC 62
R % - JE .105, SC .104
RBI - JE 83, SC 67
RBI % - JE .139, SC .117
R+RBI % - JE .244, SC .221

The man with the higher OBP (Casey) has two fewer plate appearances. The man with the higher SLG (Encarnacion) leads in all other categories. Advantage - SLG.


Mark Kotsay vs. Roger Cedeno - OPS .715
PA - MK 446, RC 418
OBP - MK .342, RC .327
SLG - MK .373, RC .388

Runs - MK 53, RC 55
R % - MK .094, RC .097
RBI - MK 31, RC 33
RBI % - MK .058, RC .061
R+RBI % - MK .152 , RC .158

The man with the higher OBP has 28 more plate appearances. The man with a higher SLG (Cedeno) leads in all other categories. Advantage - SLG.


For the entire set of five pairings, the OBP group has only 11 more plate appearances. They lead runs twice, and R % once. The SLG group leads runs three times, R % four times, RBI five times, RBI % five times, and R+RBI % five times. The pairings of players include players of all different skills, all different skill levels, and all different team levels.

I have trouble believing it, but I can only draw one conclusion: Taken along with the head-to-head game analysis results, and contrary to what everyone believes today, these numbers seem to prove that SLG could be more important than OBP.

What do you think?
Dave's Email

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