Comments on: April Homers

By: Sal Paradise

Sal Paradise — Tue, 20 May 2008 02:55:39 +0000

#4 Greyson:

While I understand your thought process, if weather were to have that much of an impact, then you’d expect a better home record than away record.

Marlins:
Home: 13-11
Away: 11-8

Diamondbacks:
Home: 19-8
Away: 9-8

Rays:
Home: 16-8
Away: 9-11

Certainly true for the Diamondbacks and Rays.

However, there’s also the matter of whether or not they are winning because of pitching, or because of hitting.

Florida:
Runs Scored: 5 (t-3rd in the NL)
Runs Allowed: 4.8 (t-9th in the NL)

Arizona:
Runs Scored: 5.4 (2nd)
Runs Allowed: 4.1 (2nd)

Rays:
Runs Scored: 4.6 (t-3rd)
Runs Allowed: 4 (5th)

The problem is that we would expect ‘hitter’s weather’ to help batters and hurt pitchers, which it doesn’t seem like is the case in Arizona’s case, or even the Rays case. And Florida doesn’t seem to have a good home-road split.

There’s nothing exhaustive about this ‘research’ but it doesn’t seem to indicate it being a weather-related thing (though one would have to go deeper into temperature and weather and divide it that way to see if performances for these teams are correlated to temperature).

By: Steve

Steve — Mon, 19 May 2008 19:44:28 +0000

Interesting, but the correlation isn’t as strong as it that graph makes it appear if you plot HR vs. temperature. The r-squared value is only about .35, and still only about .67 after dropping the two biggest outliers.

By: Ken Houghton

Ken Houghton — Sun, 18 May 2008 17:35:41 +0000

I’m inclined to suggest looking at, say, A-Rod’s April 2007 v. (A-Rod and Rodettes) in April 2008 and wonder if there are a few other outliers like that in the AL.

But that still wouldn’t explain 2006.

By: Adam

Adam — Fri, 16 May 2008 21:59:16 +0000

The temperature graph is very startling in its correlation to homeruns. However, I’d be curious to know what theories there are for why 2002 stands out as the one year this wasn’t the case. Statistical anamoly is certainly an option, but I wonder if there was something else going on.

By: Andy

Andy — Fri, 16 May 2008 18:06:24 +0000

I would also be interested to see the rate in domed stadiums over that time. I don’t know how possible it is, since some domes are retractable. Good anaylsis though!

By: Chris

Chris — Fri, 16 May 2008 14:13:21 +0000

When you did this analysis, did you just use the overall average temperature for the month, or did you go to the extent of analyzing the game-time temperature for each game?

By: Dan

Dan — Thu, 15 May 2008 17:53:28 +0000

Very interesting, and I have to say the graph is extremely compelling. Thanks for taking the time to put this together.

I know from a BP article that runs in the AL are down quite a bit more than in the NL (where they are flat from last year). Can you show the above graph split between the two leagues to see if the average temp for NL has been higher than AL? At the very least, it seems to me the best NL teams so far play in somewhat warmer climates than the best AL teams, but I could be wrong here.

By: Greyson

Greyson — Wed, 14 May 2008 18:34:27 +0000

I frequently wonder why there isn’t more time spent analyzing weather’s impact on the game. I think you can attribute weather as a large factor in the hot starts by both the Rays and Marlins this year, but no one seems to ever bring this up. (You can probably throw the D-Backs into the conversation too, but they have a much more talented team regardless.)

By: Donald A. Coffin

Donald A. Coffin — Wed, 14 May 2008 15:40:38 +0000

FWIW, the decline appears to be entirely in the AL (see Joe Sheehan’s recent analysis of this at BaseballProspectus.com).

By: rubemode

rubemode — Wed, 14 May 2008 15:37:02 +0000

I’ll throw out this idea, your book makes the cases that expansion had a great impact on “offense”. One that I agree with. Could it now be the case that the league’s pitching has “caught up” and over come the watering down effects of expansion from the early and late 90′s?