Same old story in loss to Orioles

8 Comments»

Fabio - Yfan in Brazil says:
April 9, 2007 at 11:24 am
Hi Joseph, can you explain me somethig? Isn´t the home team a winner something like 54% of the time? So when the game starts, the shouldn´t the wpa start at .54?
If so, if you win a home game, the total contribution (sum of all the players wpa) should be a .46, and not a .54. If you start your calculations at .500, this means that, after the first out, you have credited the pitcher with an extra .04 he did not deserve. This mean that the contribution from the pitcher, from the wpa standpoint, has been even more abysmal.
Sorry to bother you with this, I don´t mean to nit´pick, just want to understand the concept better.
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Fabio - Yfan in Brazil says:
April 9, 2007 at 11:30 am
Sorry, should have said
If so, if you win a home game, the total contribution (sum of all the players wpa) should be a .46, and not a .50.
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Joseph P. says:
April 9, 2007 at 11:45 am
Hi Fabio. Yes, the WPA calculation is made with the home team winning 54 percent of the time. So the pitcher does not receive any undue credit. Winning home teams have a combined WPA of .460, and winning away teams have a combined WPA of .540.
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Fabio - Yfan in Brazil says:
April 9, 2007 at 12:51 pm
Than something must be not working properly, since the sum of the wpa for this game is -.50, and the sum from the last game is .50. Also, the wpa graph starts at .50.
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Joseph P. says:
April 9, 2007 at 1:15 pm
I’ll have to as a few questions, then. I used to run WPA through a spreadsheet, and that certainly started out with the home team at 54%. Now, I take information from another website, so I’ll have to ask him and find out a proper answer for you.
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Fabio - Yfan in Brazil says:
April 9, 2007 at 5:40 pm
Thanks. And thank you for the trouble. You have a great site, I am enjoying reading your analysis.
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Joseph P. says:
April 9, 2007 at 5:53 pm
Hmm…it appears my comment didn’t show up, or was lost in moderation.
Anyway, here’s the explanation. First, the 4% difference is considered negligible, since it is spread out among all position players and pitchers. It amounts to roughly .003 per player.
The most important reason, though, is that giving the home team such an advantage would open the flood gates to other variables. For instance, if Santana is on the mound for the Twins, their odds of winnings are much higher than if Sidney Ponson is pitching. Yet, there is no WPA adjustment for that. So, why give them the 4% home field advantage when other advantages are not noted?
I think when you take that into account, the 4% seems even more negligible.
You can find a discussion thread over on fangraphs:
http://www.fangraphs.com/forum.....d.php?t=68
http://www.fangraphs.com/forum......php?t=164
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Santos Philipp says:
May 12, 2011 at 4:45 pm
Do storage facilities allow any kind of maintenance or repairs to be performed while storage?
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