Does Size Matter?

I wrote an article for The Hardball Times Thursday examining how player performance varies by size. If you have yet to read it, check it out! Anyways, there were a bunch of questions that followed, so I’ve decided to just answer them all here.
How many players were in each category?
I mentioned that Kirby Puckett made up more than half of the “pudgy” sample, which led to a lot of questions about the significance of my samples. Here they are, for each category:
Big = 657 players; 644,886 PAs
Lanky = 10 players; 3,011 PAs
Pudgy = 7 players; 12,404 PAs
Small = 462 players; 652,722 PAs
Now obvioulsy the samples for the Big and Small groups are much greater, and for obvious reasons. There are plenty of guys that are tall and heavy or short and light, because those two characteristics are proportionate. It is much harder to find a disproportionately sized player. Nevertheless, I think that both the “lanky” and “pudgy” samples are large enough to be significant.
Tom Tango suggested on The Book blog that I make the breakdown such that my samples are all the same size, and I may yet take that suggestion. One e-mailer suggested that I use BMI, and that might be a pretty good idea as well.
My one worry is that I want to use just extreme players. If I start expanding the requirements for the “lanky” and “pudgy” categories, my samples might increase, but I’m not sure that the players I’ll be including will actually be guys that are lanky or pudgy rather than slightly under- or over-weight.
Shouldn’t you be adjusting for era?
Some suggested that players are bigger nowadays, and I should adjust that. Actually that’s not really the case. Players have gotten slightly taller (about an inch) and slightly heavier (about five pounds) over the past 50+ years. I don’t think that’s significant enough to merit adjusting for.
Okay, so big players are better hitters, what does that tell us about how big players develop?
Well, to get that answer, you’ll have to wait for part two. My interest in writing part one was to examine the differences between the categories. In part two, I’ll look into how size affects development.


3 Responses to Does Size Matter?

  1. JoeArthur says:

    I was very surprised by the idea that players have only gotten an inch taller and five pounds bigger over 50 years, but my own query against the Lahman data basically confirms that. I just looked at average height and weight by birth year, as opposed to trying to relate the players to a particular season, or excluding any players with little playing time. With that approach, height increase is about 1.3 inches between players born in the 1920s and born in the 1970s; weight is about 12 lbs higher.
    [There’s only one height/weight in the database, although weight may vary over time. It looks like the Lahman database may have career ending weight, so in some cases that weight will be misleading for earlier years in long careers.]

  2. lisa gray says:

    well, truth is i think that guys lie a LOT more about their height and weight these days because there is so much prejudice.
    but your study is looking at home runs. there’s a heck of a lot more to playing baseball than hitting home runs

  3. David Gassko says:

    Right, but as long as the lying is systematic (that is, everyone lies the same), it doesn’t matter. And of course there’s more to baseball than hitting home runs. I’ll look at how size impacts other facets of baseball in a later installment (part four).

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