The win probability increases with a home run in the eighth inning more than it does with a home run in the first inning.

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The “win probability” is based on the historical outcome of games (starting sometime in the late 70s) in similar situations, based on the number of outs and the score differential (at least with WEF). Because there is more variation in possible outcomes in early innings, the “probability” of winning is less. Either run still contributes the same amount to the total runs scored.

The win probability values are based on a series of events, not a single event. If you don’t factor in what happened in the rest of the game, they have no meaning. So the value of the run in the 8th is based on the value of not allowing any runs up to that point. If you score the run in the first inning and add the value of not allowing runs for 8 innings, they are the same.

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I don’t think you have a clue what you are talking about. The win probability increases with a home run in the eighth inning more than it does with a home run in the first inning. The win probability does not change afterwards because someone threw nine innings of shut out ball. If anything the win probability would take a jump when the pitcher works out of a two on, none out jam in the eighth and hands it off to his closer.

And the value of the home run in the eighth inning is dependent not on having allowed no runs up to that point, but in how that home run changed the margin between the two teams. If it turned a ten run deficit into a nine run deficit, it didn’t have a lot of effect on win probability. Same thing if it turned a ten run lead into an eleven run lead. But if it turned a one run lead into a two run lead, you can bet that the Win Probability changed markedly. And you can also bet that the solo shot in the third that changed the score from 2-1 to 3-1 did not change the win probability as much as the same home run in the eighth.

Just to be clear, I agree absolutely that A-Rod has not been performing at the same level in “pressure” situations (though A-Rod not performing at his best is still better than a lot of people). I just don’t agree that the home run he hits in the first counts any more or less than the one he doesn’t hit in the ninth. The one he doesn’t hit with RISP versus the solo shot hurts without question.

Coming through when the team really needs you is expected of an MVP. If Mariano had an ERA equal to that of a great starter ~ 3.00, he would not be regarded as the greatest closer of all time. His job is highly leveraged and demands more. A placekicker who leads the league in distance and accuracy during the first 55 minutes of a game, but misses 12 of 13 attempts in the closing minutes would lose his job (maybe the team would go baseball-style and have “closer” kicker who just kicks the game enders)

A field goal is a field goal. A home run is a home run. But the ability to hit it when there is more pressure on you is obviously valuable even if the field goal is still only three points. For most athletes, the difference in performance between the different stages of the game is small and the numbers revert to the mean as the sample size gets bigger. A-Rod has shown an almost all-or nothing pattern in the last four years with respect to hitting in important situations. Two excellent years. Two bad years.

So the good news is that WPA is not a good predictor of future performance. We have nine more years of A-Rod and hopefully we will get at least 5 of his “deliver in the clutch” years. The bad news is that unless he (and a few others) start hitting when we need it (like with RISP), our slim playoff hopes will soon disappear.

Basic concept is that a home run in the first inning that makes the score 1-0 increases the probability of winning less than a home run in the 8th inning that makes it 1-0.

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Win probability tells you the likelihood that a team would win a game in a simulation based on historical data where the outcome was already determined and factored into the analysis. That’s why it has no predictive value.

The win probability values are based on a series of events, not a single event. If you don’t factor in what happened in the rest of the game, they have no meaning. So the value of the run in the 8th is based on the value of not allowing any runs up to that point. If you score the run in the first inning and add the value of not allowing runs for 8 innings, they are the same.

Actually the part about the impact of runs scored at different points in a game.

Hopbitters,
Read John Oneil’s post. Repeat as necessary.
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“WPA is not a perfect stat by any stretch. A batter on a good team that a takes an early lead in most of its games will suffer compared to a great player on a team with less talent how drives in runs late. It is also not a predictive stat nor a measure of skill.”

That part?

Hopbitters,
Read John Oneil’s post. Repeat as necessary.

Steve,

Thanks for researching the real numbers. I couldn’t remember exactly what was said on YES. I knew the difference between ’07 and ’08 for A-Rod was enormous. From your numbers its clear they were talking 8th & 9th, not 7th, 8th and 9th.

As for the value of runs scored early vs. late, or in blow out vs. tight games, I recommend looking at the stuff the guys at The Hardball Times and fangraphs.com have done to track Win Probability Added and Leverage Index. Basic concept is that a home run in the first inning that makes the score 1-0 increases the probability of winning less than a home run in the 8th inning that makes it 1-0. Not hard to understand that. WPA measures how a batter has increased/decreased his team’s probability of winning over a season.
The numbers for A-Rod can be found here http://www.fangraphs.com/statss.aspx?playerid=1274&position=3B. In his two MVP Years, A-Rod had WPA of 5.52 and 6.85. So far this year, he is 0.75. Ouch. By comparison, Ortiz in his career years (’05 and ’06) had WPA of 8.21 and 7.76. This season’s leaders are Lance Berkman at 5.99 and Manny at 5.18.

WPA is not a perfect stat by any stretch. A batter on a good team that a takes an early lead in most of its games will suffer compared to a great player on a team with less talent how drives in runs late. It is also not a predictive stat nor a measure of skill. A-Rod is obviously skilled. But the general perception that he is not getting runs in highly leveraged situations is born out by the numbers.

Basically, his numbers this year are much less meaningful than they were last year or in 2005. Giambi is up a little, Abreu and Damon a little more. Jeter, Cano, Melky and Matsui are down.And But none have dropped nearly as much as A-Rod. In fact his drop exceeds the combined total of all four of them. It was unrealistic to expect another year like last, but to fall as far as he has is a major reason why we are where we are and another measure of our anemic offense.

So, you can also say that the missed field goal in the 10th minute of the second quarter hurts no more or less than the missed field goal as time expires, right?

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Unless the field goal counts for four points as time expires, they’re exactly the same.