AND THAT'S A WHITE SOX WINNER!

[Milkman delivers]

That's the 2nd time I've been asked that.

 

GPA stands for Gross Production Average. It's a stat used from the Hardball Times.

 

A variation of OPS, but more accurate and easier to interpret. The exact formula is (OBP*1.8+SLG)/4, adjusted for ballpark factor. The scale of GPA is similar to BA: .200 is lousy, .265 is around average and .300 is a star. A simple formula for converting GPA to runs is PA*1.356*(GPA^1.77).

 

For comparions sake, Uribe has a GPA of .168, Cabrera a GPA of .242, and Pierzynski a GPA of .304.

 

Bulls***.

[DBAHO]

Well here's everything I can find on GPA;

 

GPA attempts to solve two frequently cited problems with OPS. First, OPS gives equal weight to its two components, On Base Percentage (OBP) and Slugging Percentage (SLG). In fact, OBP contributes significantly more to scoring runs than SLG does. Sabermetricians have calculated that OBP is about 80% more valuable than SLG. A second problem with OPS is that it generates numbers on a scale unfamiliar to most baseball fans. For all the problems with traditional stats like batting average (AVG), baseball fans immediately know that a player batting .365 is significantly better than average, while a player batting .167 is significantly below average. But many fans don't immediately know how good a player with a 1.013 OPS is.

 

The basic formula for GPA is ((1.8)OBP + SLG) / 4:

 

Unlike OPS, this formula both gives proper relative weight to its two component statistics and generates a number that falls on a scale similar to the familiar batting average scale

 

And the explanation from the creator, Mr. Gleeman;

 

Over the last several years, the stat "OPS" (on-base percentage + slugging percentage) has become widely-known and constantly used. As more and more people begin to realize the value of things other than batting averages and RBI-totals, tons of fans and experts have started to use OPS as their preferred stat for measuring a player's hitting. It is routinely used at such places as ESPN.com and OPS has even made its way onto the back of some baseball cards.

 

At the same time, I find that, while OPS is a very quick and easy way to look at offense that is infinitely better than batting averages and RBIs, it still leaves an awful lot to be desired. For one thing, it gives equal weight to both on-base percentage and slugging percentage, which simply is not an accurate representation of the value of each.

 

In other words, a player who has a .400 on-base percentage and a .450 slugging percentage is a more valuable offensive player than someone with a .330 on-base percentage and a .520 slugging percentage. Yet, with OPS, they both come out with the same .850.

 

Because of that, I rarely use OPS. When I talk of a player's offense, I typically show his stats in the AVG/OBP/SLG form (for example, .300/.400/.500). Rarely will I say "Player A's OPS is 35 points higher than Player Z's," simply because I don't think it has all that much meaning or value.

 

Still, I often find myself interested in something that attempts to put a player's offense succinctly into one number. In those cases, I usually turn to Baseball Prospectus' "Equivalent Average." EqA uses an uneven and more accurate weighing of on-base percentage and slugging percentage and it also adjusts a player's performance for the ballpark and league they played in. I will often cite a player's EqA on this blog and I also use other stats that are based on EqA, such as "Equivalent Runs" and "Runs Above Replacement Position."

 

That said, EqA is a relatively complicated formula. It not only involves a number of steps and the use of more than just OBP and SLG, it also involves ballpark adjustments that can't be made without additional information.

 

No, what I have been looking for is a stat that can accurately wrap someone's on-base percentage and slugging percentage into one nice package, while still maintaining at least some of the "quick and easy" nature of OPS. Believe it or not, I think I have stumbled across such a stat.

 

Earlier this year I read a two-part series of articles by "Tangotiger" over at Baseball Primer. He titled the articles "OPS Begone!" and in them he discusses the problems with using OPS as an all encompassing stat.

 

He ran some very interesting studies and found that the "best-fit" for a player's overall value to an offense is not on-base percentage plus slugging percentage, but rather something more like on-base percentage multiplied by 1.7-2.0, plus slugging percentage.

 

After reading that, I began to use OBP*1.7 + SLG quite often. A quick look through this blog's archives reveals that, over the last couple months, I have used it here and here and then, most recently, in last Friday's entry.

 

Multiplying on-base percentage by 1.7 and then adding it to slugging percentage is obviously not as quick or as easy as simply adding the two numbers. That said, it is a much better and more valuable stat than OPS and it still maintains quite a bit of simplicity and ease, particularly when compared to something like EqA.

 

Of course, OBP*1.7 + SLG is not without its faults. For one thing, as I discussed last Friday, the number you get from the formula is a little hard to get a good feel for.

 

For example, if someone hits .300/.400/.500, their OBP*1.7 + SLG comes out to 1.180. But really, if you saw somewhere that a hitter had an OBP*1.7 + SLG of 1.180, would you know if that were good or bad, let alone have a decent grasp for how good or how bad it was? I know I wouldn't.

 

Luckily, I think I have found a stat that:

 

a) Combines on-base percentage and slugging percentage into one number

 

B) Accurately weighs on-base percentage and slugging percentage

 

c) Is a relatively easy formula without the need for additional information or stats

 

d) Provides a "final" number that is easy to understand

 

Last Friday, I introduced ((OBP*1.7) + SLG) / 4 as the "Aaron's Baseball Blog Number" ("ABB#" for short). Since then, I have made one slight revision to the formula that I think makes the stat much better.

 

The value in OBP*1.7 + SLG is that you get a much more meaningful number than simple OPS. The value in dividing that number by four is that you end up with something that looks a whole lot like a batting average, which is a number that everyone can put into context pretty easily.

 

.325 is great. .300 is good. .275 is okay. .250 is bad. And .225 stinks. It's pretty simple. The only problem with using ((OBP*1.7) + SLG) / 4 is that the final number, the "batting average" that comes out, is just a tad low.

 

However, if you change the on-base percentage portion of the formula to OBP times 1.8, instead of 1.7, it spits out a number that is a better match for the batting averages of this era, while still maintaining the proper weight for on-base percentage (and still staying within Tangotiger's recommended range of OBP*1.7-2.0).

 

For example, the National League as a whole had a batting average of .261 past season. The NL also had a .332 on-base percentage and a .417 slugging percentage. If you run those two numbers through the ((OBP*1.8) + SLG) / 4 formula, you get .254. That's close enough to the batting average scale that I think it works very well.

[DBAHO]

Bulls***.

I copied that definition from THT. Obviously not everyone agrees.

 

I think it's a pretty damn good stat to use when judging someone's offensive performance though.

 

Because although Quentin's hitting below .250 for example, but because his OBP and SLG are so good, he'll have a real good GPA.

[max power]

I guess I agree that its a better stat. The 1.8 number makes sense, and he just divides by four for no other reason than reducing the number into something more recognizable.

 

He should have named it something else.

Edited April 19, 2008 by max power

[iamshack]

I copied that definition from THT. Obviously not everyone agrees.

 

I think it's a pretty damn good stat to use when judging someone's offensive performance though.

 

Because although Quentin's hitting below .250 for example, but because his OBP and SLG are so good, he'll have a real good GPA.

 

That's very interesting. Thanks for posting that.

 

I've often tried to rationalize which was the more important part of OBS, OBP or Slugging, because the author is right- you do find players with higher OBP's and smaller Slugging percentages and then players like Joe Crede with lower OBP's but sometimes higher Slugging percentages- and these players can come out with the same OPS. But which is better? Or are they the same?

 

Well, according to this, the OBP is more important than the slugging. I wish they would have explained why that is a bit more.

 

I'm not really comfortable with understanding the value of this number simply by equating it to batting averages, but I suppose I will eventually understand the relative value of the numbers merely by seeing them for all different players.

[DBAHO]

Well before today Swisher had a .280/.448/.420 line while Joe Crede had a .304/.355/.625 line.

 

Who would you argue has been the better offensive player so far?

 

GPA wise, Swisher's is .298, Crede's is .307.

 

So despite there being at least a +.100 difference in OPS, the difference in GPA is less than 0.1.

[fathom]

Well before today Swisher had a .280/.448/.420 line while Joe Crede had a .304/.355/.625 line.

 

Who would you argue has been the better offensive player so far?

 

GPA wise, Swisher's is .298, Crede's is .307.

 

So despite there being at least a +.100 difference in OPS, the difference in GPA is less than 0.1.

 

Swisher's been better. Besides for the intangibles, he's seen an insane amount of pitches.

[DBAHO]

FWIW, Crede has 3.7 P/PA, Swisher has 4.3 P/PA.