THE BOOK--Playing The Percentages In Baseball

Us Skys are going to take over the world.  This other one appears to be smarter than me, though.

Maybe one of you can change your name to Stratosphere.

I was about to say I thought Sky would be a rare enough name in the baseball blogosphere to not have to try and pick “which one?” but if there are two Grahams out there too I guess anything is possible.

I can’t claim to know Sky Andrecheck personally, but I did happen to sit in a few of the same statistics classes as he did in college. He definitely was one of the smart ones in the class.

Great article—I’m so glad that someone has finally gotten around to doing this. This should settle the MVP debate once and for all, heh heh. I actually wish that all of the sites running playoff odds would also show the likelihood of winning a championship. When a team in a weak division squeaks into the postseason with an 84-78 record, their odds of winning the World Series are still relatively low compared with the other teams.

Anyway, it’s also impressive that Sky was able to run a sim from every day of the season—must’ve taken quite a lot of time and computer power.

In addition to the colour scheme on the graphs, I really liked:

...can you name the most important at-bat of the season last year?

It was Game 7 of the ALCS (Champ LI of 88.9) when JD Drew came to bat with the bases loaded, two outs, in the bottom of the 8th inning of a 3-1 game (game Leverage Index of 5.19). The total Championship Leverage Index of the at-bat is 461.4 (5.19 x 88.9), meaning that the at-bat was 461.4 times more important than an average regular season at-bat.

I’d love to see more of this, maybe a running scoreboard on Fangraphs. Wouldn’t have realized that that at-bat was our “Bucky Dent” moment of 2008. Hopefully Sky is able to show a few more of the key at-bats from last season.

unless Milwaukee and New York had been playing each other, in which case the Champ LI would have doubled to 22.2

Interesting that the final game of the regular season, if the Brewers and Mets played eachother, would’ve been roughly equal in importance to (a) a division series at 1-1 or 2-1, (b) an LCS game at 2-0 or 3-1, or (c) a World Series game at 3-0. Actually, it’s also very interesting to see that the deciding game of a division series is equal in importance to a World Series with one team up 2-0 or 3-1.

Can’t wait to see Championship WPA. I wonder also if it’s possible to see a list of the 10 or 20 biggest games from last year (playoffs included). I wouldn’t mind watching some of them on MLB-TV before the season starts.

I’m not normally a big fan of these kinds of “toys”, but this is great stuff.

And it should be mentioned that Studes did essentially the same thing a while back on THT. Sky and Studes have a discussion in the comments section about each other’s work.  It is not real clear why they are coming up with different numbers…

Thanks for posting this, Tango.  There was a certain other site that I relied on to aggregate links like these, but they didn’t link this one, AFAICT.

GGC: Like Baseball Prospectus, BTF doesn’t seem as interested in sabermetric studies as it once did.  The latter would prefer linking to and making fun of Murray Chass. 

I’m too diplomatic, aren’t I , Rich?

In the fall of ‘05, I tried a little experiment WRT what I called Pennant Probability Added.  I went to Jay Bennet’s site (http://www.amstat.org/sections/sis/pgp/index.html).  He had Player Game Percentages for the previous 10 World Series.  The numbers come out differently from what Studes has for WPA, but I suppose that they’re close enough for govt work.  I weighted the stats for each game using a simple assumption that each team has a 50/50 chance to win any game (for example, a team up 2-1 has a 75% to win the series while one down 0 games to 3 has a 6.25% chance).

If you go by this method, Tony Womack had the best World Series for any player over thatdecade, back in ‘01.  The method favors players in contentious Series.  Gong by a straight Win Probability method, the best WS by a player this decade was by Josh Beckett in ‘03 or Lance Berkman this year.  Beckett had 39.9 player game points while Berkman averaged 9.3 PGP/game.

If it works, my name should link to a GOogle spreadsheet of this.

Re: the difference in Sky’s and Studes’ results, Sky suggests that using post-victory WS% to pre-game probability (his method) should give the same result as using the difference in probability after a victory vs. after a loss (Studes’ approach).  But I wonder if that has to be true? I would think that in some cases the impact of a loss would be greater (in absolute terms) than the impact of a win.  For example, Studes assigns much more leverage to Nats games in late May, when they were already c. 8 games out.  But if further losses meant a relatively big decline in WS probability, then the win-vs-loss spread would be large, while win-vs.-current would be smaller.

To clarify post #10:  Sky bases his system on the difference between post-victory and pre-game probabilities, while Studes uses difference between post-victory and post-loss probabilities.

Sky has posted the next installment of his article:

http://baseballanalysts.com/archives/2009/04/championship_wp.php

As everyone knows, Sabathia was dominant in his stint with the Brewers - he was 11-2 with a 1.65 ERA. What’s interesting is to see that he won about 6% of a World Series title due to his work during the regular season - the biggest game of course being his masterpiece against the Cubs on the final day of the season. However, in his one playoff appearance, he choked away much of his value when he was pounded for 5 runs in 3 2/3 innings - on that single day alone, he gave back 3.5% of a championship, leaving him with a net value of 2.33% of a World Series title with the Brewers.

In the regular season, the biggest play of the year belonged to Ryan Braun’s 2-out 8th inning home run giving the Brewers the lead against the Cubs on the last day of the season. The game was meaningless to the Cubs, but to Braun and the Brewers the play earned 2.4% of a World Series title.

Interestingly, Braun’s home run is slightly more valuable than CC “Splish Splash I Was Takin” Sabathia’s overall contribution (including the playoffs).

I was surprised though that Sky didn’t post a top 10 list of the players with the most “championships added” last year. It’d be interesting to see a regular season version (so that the reg season results aren’t washed out by obscure but high-impact playoff events such as Balfour’s wild pitch).