Much has been made of Jamarcus Russell being as big as a lineman (and nearly as fast!). So much in fact that you might think, as some sources in the media have suggested that being amazingly huge will make you an amazingly good quarterback (here for instance). Now we've heard this about height for years, after all, Peyton Manning is the 6 foot 5 quarterback with the laser, rocket arm. This year, a big deal is being made out of weight as well. Now a normal person might think that a quarterback's ability is more affected by his ability than his height or weight. In fact, that's what's called a tautology.
However, seeing as the main stream sports media is above recognizing tautologies, let's test this bitch empirically. I'm going to fire up Stata and bust a regression on your dome. I'm going there, just because this talk is all so god damned stupid.
I'm only reporting the data for QB rating, because in spite of being a pretty shitty measure, it accounts for most forms of performance in a number that is decently spread out throughout the league. Rest assured I also regressed height and weight against tds, sacks, yds/game, comp%, and ints individually. The bottom line is that there is no correlation, 0, jack, zip.
Now, obviously, I excluded Quarterbacks without much playing time, this data consists of only QBs who had played six or more games and attempted more than about 15 passes per game. Since there is relatively little variation in height, compared to weight, I standardized the data first. The p-value for height is .330, the p-value for weight is .792!!! This means that it is 4 times as likely that weight has NO EFFECT on QB performance as it having an effect. The p-value for height is less than half as much, which may seem impressive, but generally the level of statistical significance is .05. Even more impressive, the coefficient for height is -2.1. NEGATIVE. That means that although the correlation is fairly likely to be a result of random variation, assuming that it isn't, taller quarterbacks actually perform WORSE.
Now you're probably reluctant to accept this, because the conventional wisdom is that height helps quarterbacks. However, this makes perfect sense. Unless a quarterback is about 4'11" it doesn't matter! And yet, coaches believe it matters so they tend to stick with subpar quarterbacks longer if they happen to be tall. It's just like deciding that the first man in your line up NEEDS to be fast, and then putting your worst hitter there. The physical attribute doesn't correlate strongly enough with performance to justify it. However, actual, statistical performance correlates perfectly with performance.
So basically, anyone who says that someone is "built" to be a quarterback, is WRONG--very, very wrong. Feel free to punch them.