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What's Your GPA?

Earlier this week, Aaron Gleeman introduced a new metric that he quasi-narcissistically calls GPA, or the Gleeman Production Average. While hardly perfect (what metric is?), GPA serves a definite purpose in the sabermetric community. Though it is not as accurate as EqA, it is far simpler to calculate, and is a bit of an upgrade over OPS (OBP + SLG).

OPS, while clever and easily-derivable, has a major inherent flaw. It assigns equal weight to on-base percentage and slugging percentage, when it is quite clear that OBP is the more valuable asset. The most basic example to this effect is the following:

Team A and Team B both have an OPS of 1.000. Team A has an OBP of 1.000 and a SLG of .000 (meaning they walk every plate appearance), while Team B has an OBP of .333 and a SLG of .666 (they get a double for every three at-bats). In this scenario, Team B will score an awful lot of runs. Team A, however, will score an inifinite number of runs, as they will never make an out (barring baserunning gaffes). So, while both teams have an identical OPS, their production is significantly different.

Granted, this is an extreme example, but it does get the point across that OBP is more important to a team than SLG. But how much more important? Tangotiger, one of the more prominent sabermetric minds on the internet, wrote a couple of articles (this one and this one), where he breaks down the importance of OBP relative to SLG. He concluded that OBP is roughly 1.7-2.0 times more important than SLG.

Aaron decided to use 1.8 as the multiplier, and, in an effort to make the result more recognizable, divided the whole lot by four, to force a scale similar to batting average. So, the formula for GPA was born:


[(OBP * 1.8) + SLG] / 4

Aaron has posted a quick reference guide which provides 2003 GPA rankings by league, team, and position. Based on Aaron's work, I have put together a Microsoft Excel spreadsheet based on ESPN.com's Sortable Stats for all qualified MLB batters in 2003. The spreadsheet contains all of the regular hitting statistics (AB, R, H, 2B, 3B, HR, RBI, SB, CS, BB, BA, OBP, SLG, and OPS), as well as a column for GPA. I have also included a column for the team and for the league, so you can sort by those as well. The spreadsheet can be downloaded here (*fixed*). All qualified batters are included which, as defined by ESPN, are all position players who appeared in two-thirds of their team's games, and catchers who appeared in half of their team's games.

If you have any suggestions for improvements to the spreadsheet (i.e. additional columns), please let me know. I hope to have a spreadsheet including all players who appeared in MLB games this season soon, not just qualified players.

A brief tutorial on sorting in Excel can be found here.