Monday, February 25, 2008

Length Matters

So I was reading the Hardball Times today and ran across this gem. The article discusses home run length and uses statistics from Hit Tracker to break down "no doubt," "plenty," "just enough," and "lucky" home runs. The first two categories seem throwaway since they contain homers that were plenty far enough so no matter what, they were leaving the yard. It's the second two categories ("just enough" and "lucky") that Rob Neyer talks about here (subscription needed) that warrant discussion. The Jaffe piece argues that teams and players with high percentages of "just enoughs" will have a higher probability of regression the next year. Notable teams and players include the Red Sox (36% compared to a league average 29%), Giants (43% cheap), Brandon Phillips (14 of 30 cheap), and David Wright (12 of 30 cheap). Jaffe then suggests that one can better predict a team or player's home run rate by normalizing their "just enoughs" to the league average of roughly 29%.

My problem with his analysis is that he does not take into account what I call "just misses." For every ball that makes it over the wall by ten feet or falls one wall's length beyond the wall (the threshold for "just enough"), there is in all likelihood a ball that falls short by the same amount (a "just miss"). If we normalize home run rates by adjusting "just enough" rates to the league average, we need to do the same for "just misses." Without "just miss" rates, we really have no concrete way to know whether or not Gary Sheffield's ridiculously low "just enough" rate of 4.17% is attributable to the kind of contact he makes or to horribly bad luck with fly balls within the "just miss" threshold. For all we know, he hit tons of balls that died short of the wall that could potentially be homers next year. We need to know "just miss" rates for individual players as well as the league average so we can normalize correctly on both ends.

Furthermore, Jaffe doesn't take the full effect of weather into account. For every fly ball that becomes a homer just because of favorable weather conditions ("lucky"), there is in all likelihood a fly ball that fails to go over the fence because of adverse conditions ("unlucky"). For example, David Wright had 10 "lucky" home runs last year. However, to accurately predict the overall effect of weather on Wright's home run rate, we have to know how many "unlucky" fly balls he hit. Additionally, we have to know the average rate of "unlucky" fly balls for the league so we can normalize his rate for predictive purposes. This will give us a complete picture of Wright's overall luck factor by taking in both the positive and negative effects of weather.

TLDR: Unless we can normalize for "just misses" and "unlucky" fly balls, we do not have a way to accurately predict home run rates through Jaffe's method. I hope he continues his analysis by taking this into account because it's a fascinating line of research; he simply needs to get both halves of the whole to see if there's a correlation to be found.

Sorry that there's not more to be posted today. Some things came up and I don't have more time to blog at the moment. But don't worry, I'll be plenty bored at work tomorrow so there should be more updates then.

7 comments:

Adam said...

Oh, and just my 2 cents on Dontrelle "Who needs eyes behind your head" Willis.

He's been on the decline since his first season. The only 3 things he had going for him were his funky delivery, being left handed, and being young. Well, people aren't really fooled by his delivery anymore, he's still left handed, and he ain't that young anymor either!

The D-Train never had incredible stuff, he just had good stuff for a lefty which most can get away with since lefties don't tend to need stuff as good as a righties. He isn't getting any younger, his stuff isn't getting any better, and he'll just get more used up. Unless he wins 12-18 games and has an ERA of 3.5 or lower, I don't see him as that great a pick-up for the Tiggers.

Heck, he could win a Cy Young and prove me wrong, but I'll take that bet.

sanstodo said...

Just to play devil's advocate, he still is only in mid 20's and the AL hasn't seen his delivery much. The delivery is his greatest strength and weakness. It creates deception but it also is hard to repeat. If he can manage to keep it repeatable, he might get his fastball command back and return to dominance.

I don't see it happening because, as you said, his stuff doesn't translate as well to the varsity and I think control problems are going to plague him.

Adam said...

Don't mean to pile on even more hate on ol'Dontrelle, but he going to get pounded.

I don't think anyone fears him in the AL. No good bats will be fooled by the delivery, they've had ample time to study tape. After a few times seeing him, the major league talent will pick it up. He can't control his pedestrian high-80's, low-90's(on a great day) fastball, and his slider was only average to average-plus. If he can't control the fastball, then his change will get pounded.

All the hype and hope will fall flat in Tigger land over their new "Awesome" pitcher.

Mooch said...

As far as the delivery comments go, I mostly agree. 'Funky delivery' can only get you so far. But sub-mariner pitchers and El Duques of the world are going to continue to be effective as long as they do what sanstodo mentioned---repeat their delivery. I don't care how much tape you can watch of someone with an odd delivery, the entire mindset of a batter has to change to look at a different release point for these kinds of pitchers. Only the most dedicated, focused and talented batters can do that. El Duque is damn old and still somehow manages to be effective (he is obviously nowhere near where he used to be but I truly believe the wear and tear on his body is the reason for that, not the fact that people 'picked up' on his delivery).

I am not a huge fan of the pitching coaches that Detroit has so I do not see any way that Willis will be able to refine his mechanics to a point where he can be as effective as he once was---or even reach a 3.5 or lower ERA. But I don't think the Tigers need that from him with that lineup. A 4-4.5 ERA will more than suffice as long as he can give them 200+ innings. Their bullpen is going to be taxed with the injuries and questions surrounding Zumaya, Rodney and Jones. If Willis can be a Livan Hernandez type of workhorse I think he will be great value for the Tigers. It also should be noted that the trade Detroit made was focused on Cabrera. If he can keep his weight in line I think the deal will show completely worthwhile even if you were to remove Dontrelle from the trade.

Mooch said...

and as a response to this actual post, hehe, I do not think weather should play much of a role in this kind of a metric. The extremes (Wrigley, possibly the new Nationals stadium would be exceptions PERHAPS) may affect things a bit more but I think overall it evens out. Teams tend to play fairly similar numbers of games in domes, in poor weather, etc. And over a players few seasons I think that especially tends to even out. Maybe more important than just weather as an extra factor should be ballpark. The dome vs Wrigley is much more extreme than an evening at Yankee Stadium vs. a daygame at PETCO. A park's average numbers for the just misses might be more telling? Not sure, haven't thought it out much.

sanstodo said...

Mooch, I generally agree but I want to note that the trade left the Tigers with a very thin farm system. If they have any significant injuries beyond Rodney and Zumaya in their pitching staff, they're going to have some serious problems stopping runs. Unless they manage to win a World Series in the next few years, I'm not sure if that trade will look so good down the line, particularly if Maybin and Miller fulfill their potential.

Mooch said...

agreed that the trade left the farm system pretty bare but it was a Yankee-esque move. So if it wins them a world series soon it will definitely be worth it as you said. They could also take a lesson from the Yankees in how NOT to deal over the next few years. They need to start stocking up the farm system NOW, not reaching for overpriced free agents regardless of how the next year or two turn out. Maybe even during this year they should start making those moves---trading off Inge or Thames. If Zumaya comes back healthy perhaps even dealing Jones if any contenders lose their closer. Crazy ideas and high-risk ones at that but the bottom line to me is that even if Maybin AND Miller perform to expectations you still have an extremely young (he'll be 25 during April. 25!!) Cabrera for years to come. And with a marquee player like him you can also justify stretching the limits of your budget and overpaying here and there for free agents WHILE restocking the farm system.