Comments on: wRC and wRAA

By: Ben

Ben — Thu, 02 Jun 2011 20:23:40 +0000

Hi again,
I know you don’t include Reached Base on Error in your calculation, but why is it included in Mr. Tango’s formula? Why should a batter get credit for the other team making a mistake? Thank you very much.

By: Ben

Ben — Thu, 02 Jun 2011 20:21:12 +0000

Hello,
Could you please explain the wOBA Scale calculation? I see that pacity0champs already asked, but no one anwered, so I’ll ask again. Thanks!

By: pacityOchamps

pacityOchamps — Fri, 04 Mar 2011 21:03:16 +0000

Hey!
I may be stupid (well I am but this individual effort may also be less than intelligent) but, what is the value for wOBAScale?
I have been reading on all stats starting from linear weights on and from linear weights to WAR the only thing I’m missing is this value.

Thank you preemptively for filling me in.

DLR

By: Ben

Ben — Mon, 05 Jan 2009 04:26:02 +0000

Do these numbers have factor in the home park? In other words, would 2 equally skilled players have the same wRC and wRAA if one played in Coors and the other in Petco?

By: Sam

Sam — Sun, 04 Jan 2009 00:14:49 +0000

wOBA is better served as a player evaluation tool, not a team one.

By: Baltimoron

Baltimoron — Thu, 18 Dec 2008 03:09:07 +0000

Hi David,

I believe Bill James forecasts (or at least did) for a more limited set of players than other systems.

If so, is averaging his forecasted players basically “selectively sampling” a group of above average players, so that it ends up excluding a lot of marginal, replacement type players whose predicted performance would otherwise pull down the average of forecasted players closer to actual league averages?

I think that is what I gathered from this (http://tinyurl.com/3mb6ky) thread at The Book blog, which seemed to indicate Marcel only failed to forecast like 5% of plate appearances while with James, “10% of MLB PA were either unforecasted or unmapped.”

I’m not sure if its correct but my sense too is that it might be helpful to use the same baseline for an apples to apples comparison.

Thanks again for your great site.

By: David Appelman

David Appelman — Wed, 17 Dec 2008 23:05:37 +0000

Hmm…. well, I can tell you why it’s 2.6 and then I guess we can discuss if it should be 2.6, since I may not be dealing with lgwOBA correctly in the projections.

Basically, the lgwOBA for the Bill James projections comes out to .346 instead of .328. That’s where the difference is, and since wRAA is runs above average, the average runs is considerably higher in the Bill James projection than it is the Marcel. Maybe I should be using the same baseline so we have an apples to apples comparison.

By: Baltimoron

Baltimoron — Wed, 17 Dec 2008 22:23:21 +0000

Hi,

Question about the plate appearances data are you using to calculate the projected wRC/wRAA calculations based on the Marcel and Bill James’ projections?

For example, Marcel projects Brian Roberts to have 546 at bats/624 plate appearances, a .346 wOBA and a 7.6 wRAA.

Bill James projects Brian Roberts will have 623 at bats (no PA projection), a .350 wOBA but only a 2.6 wRAA.

Shouldn’t the wRAA for the Bill James projection be higher than the wRAA based on the Marcel projection, as James thinks Roberts will have a higher wOBA and also have more at bats than Marcel?

Thanks.

By: Gary Velich

Gary Velich — Tue, 16 Dec 2008 16:24:03 +0000

Dear Mr. Appelman, I was looking at Jim Albert and Jay Bennett’s book titled Curve Ball this morning and in Chapter 6 on page 168 he says OPS dominates into the mid-1930′s. Total Average has the edge from then to the present day, TA has beenthe best estimator since 1991. And on page 170 he said TA, has a slight edge over OPS. And he then stated that a better model than OPS can be made by multiplying them together- OBA times SLG. And in the next paragraph he says BRA appears to be less effective than TA, but more effective than OPS. So, it seems that multiplying OBA and SLG produces a better model than adding the two values. Then on page 174 he says that Runs Created per game- Technical version he uses has the lowest average RMSE- (.136) from 1954-1999. He compared them to (BRA, DX, TA, and OPS). and on page 175 he says that from 1954 to 1999 RC/Game is a superior model to Total Average. So, that means that both the RC/Game stat, Total Average and BRA-OBA times SLG are better than OPS. I see that you have OPS on your fangraphs site. I am wondering if you could please still add the RC/27 stat with Runs Created and also the Total Average stat and BRA stat which are all better than OPS according to Jim Albert in his Curve Ball book. Could you list them in another section like you do for Standard stats and advanced stats and maybe another one called extended stats? I hope you could as I like your site alot Mr. Appelman. Thank you for considering my request.

By: David Appelman

David Appelman — Mon, 15 Dec 2008 19:50:46 +0000

James: Pitchers are currently included when calculating the lgR/PA and I’ve been told by Tango that excluding them doesn’t make total sense. He’d be better able to inform you of the specifics.

In reality, over 600 PA you’re looking at a total of 1.2 run difference since it’s like a .002 run difference per PA between excluding and including pitchers in the lgR/PA. Not much of a difference and it’s uniform so I don’t think it’s a particularly big deal either way.