Friday, May 8, 2009

No one likes a math nerd

When Merkin Valdez struck out Matt Kemp for the second out in the 8th, the LAtriners Win Expectancy stood at 9.6%, the lowest point for them in the game. Merkin, as we know, walked the next two guys, raising the Win Expectancy to 16.3%. In other words, the walks were bad, but the game situation was still very much in the Giants favor. Ol' Boch summoned his gunslinger, Brian Wilson, who threw 13 pitches to Casey Blake before getting the called strike three. The Win Expectancy for the Smoggers then plummeted to 7.8%.

I have to tell you, I was a lot more nervous about that 8th inning than the Win Expectancy tables said I ought to be. I had visions of the killer three-run bomb ruining a great night.

And a great night it was! The Giants put on their pesky faces and out-annoyed, out-harassed, and out-irritated the Blue Goo. They had Their Young Ace on the bill, and we had The Barry Zito Triumphant Comeback Tour booked. I think I'd rather go see any hot young band, even if they were one of those throat cancer-growling metal bands, than a Fleetwood Mac reunion. Wouldn't you?

But the Giants showed me something tonight I thought they lacked--a killer instinct. The LAtriners not only lost their biggest star, but their historic home win streak. (NPR led off Morning Edition today with that story.) They were down. They were weak. They were ripe for the plucking. And we plucked their fookin' nose hairs! We beat them with some exceptional fielding--Manny B was the man with the golden glove tonight. And we got the "productive outs" Ol' Boch seems to love. We managed to get caught stealing--twice--which I absolutely hate, but when you are a pesky no-hit team, I guess you have to run like a meth-head with the DTs.

I know that no one likes a math nerd, but I want to take this time, in the afterglow of the biggest win of the year, to talk a little more about Win Expectancy. Now, this is not the be-all end-all of statistical analysis. But it gives you some food for thought. A the start of the 7th inning, the WE for the home team stood at 50%. After all the ups and downs, the game was tied, and both clubs had an equal shot to win. Uribe and Burriss (there he is again) had back-to-back hits in front of the pitcher's spot. The WE (for the home team) plunged to 35.6%. This was the critical time for LA--Billingsley needed outs. Naturally we pinch hit (imagine if we had a bopper instead of a flea here), and naturally we bunted. That bunt--everyone's favorite strategy--lowered the WE to 35.4%. That's right. The loss of an OUT was far more important there than the gain of a base. Sure, we were playing for one run, and the WE does not take that into account. But the point is that we gave up a more valuable commodity--an out--to gain a less valuable one--a base. Our chances of WINNING THE GAME were hardly improved at all. LA had no choice but to walk the next guy, Fred Lewis. Essentially, we took the bat out of his hands. Fortunately, Renteria got the sacrifice fly and not the double play grounder, and the WE dropped to 31.2%. Sandoval's hit with two outs pushed it to 17.6%, and we started to see a real chance at winning. Rowand made an out (22.5%), and Pierre led off the 8th with a walk. That gave them some life, raising the WE to 29.3%. This time we got the DP (15.7%) and, eventually, the win. I'm telling you, this shit is pretty cool, and it gets you to scratch your head and think about game tactics and situations.

But the most important thing is that this absolutely improbable ballclub got a HUGE, HUGE win against our most hated foe and division leader. Keep proving me wrong, I say, keep proving me wrong.


JC Parsons said...

If no one likes a math nerd...where do all of you come from?

A couple thoughts about your latest statistical object of affection:

* Seems like change in WE is what is really important. Is that a differential or just the slope?
That would be an interesting look into impact.

* I think that your noticing the slim chance of the big HR is important. Perhaps that is evidence that they are OVER-RATED. You noticed it, not me.

JC Parsons said...

BTW I've ALWAYS liked Barry Zito.

Bob said...

A technical point- DTs only occur in alcoholics, even though many use the term to apply to any version of substance withdrawal. The actual withdrawal syndrome for meth heads is commonly referred to as SLEEP ie they crash for a couple of days. (This is what I do for a living.)
What would have been the probability difference if Ethier had dropped the foul ball in the sixth instead of catching it and allowing the first run of the game to score from third?
What happened to Merkin? He blows a guy away with an uber-manly fastball, then throws 8 straight pieces of crap for 2 walks.
I always liked Ziro, um I mean Zito too.

M.C. O'Connor said...

Ah, thank you for the clarification. We nerds appreciate precision.

The change in win expectancy is expressed as a decimal and referred to as "win probability added." If the WE goes from 50% to 70% due to your hitting a 3-run HR, you get credit for 0.20 WPA.

Last night, there were 2 outs in the 6th and the Doggs were down 1-0 with a man on. Their WE was 35.1%. Blake doubled and tied the game, increasing their WE to 55.3%, for a WPA of .201 (the biggest swing of the game). Billingsley made an out and we started the 7th back at 50%.

It is an interesting analytical tool. It makes you evaluate game situations in a new framework. That doesn't make older notions invalid or obsolete--just incomplete. (And it gives you more ammo for the barstool, provided you can get past the VSC/GMF arguments.)