Are early NFL draft picks no better than late draft picks? Part I
Dave Berri thinks that NFL teams are inexplicably useless in how they evaluate quarterback draft choices. He believes this is true because of data he presents in a 2009 study, co-written with Rob Simmons, in the Journal of Productivity Analysis. The study is called "Catching the Draft: on the process of selecting quarterbacks in the National Football League amateur draft."
The study was in the news a couple of years ago, gaining a little bit of fame in the mainstream media when bestselling author Malcolm Gladwell debated it with Steven Pinker, the noted author and evolutionary psychologist.
In his book "What the Dog Saw," Gladwell wrote,
"... Berri and Simmons found no connection between where a quarterback was taken in the draft -- that is, how highly he was rated on the basis of his college performance -- and how well he played in the pros."
Pinker, reviewing the Gladwell book in the New York Times, flatly disagreed.
"It is simply not true that a quarterback’s rank in the draft is uncorrelated with his success in the pros."
Gladwell wrote to Pinker, asking for evidence that would contradict Berri and Simmons' peer-reviewed published study. Pinker referred Gladwell to some internet analyses, one of which was from Steve Sailer. Gladwell was not convinced, but responded mostly with ad hominem attacks and deferrals to the credentialized:
"Sailer, for the uninitiated, is a California blogger with a marketing background who is best known for his belief that black people are intellectually inferior to white people. Sailer’s “proof” of the connection between draft position and performance is, I’m sure Pinker would agree, crude: his key variable is how many times a player has been named to the Pro Bowl. Pinker’s second source was a blog post, based on four years of data, written by someone who runs a pre-employment testing company, who also failed to appreciate—as far as I can tell (the key part of the blog post is only a paragraph long)—the distinction between aggregate and per-play performance. Pinker’s third source was an article in the Columbia Journalism Review, prompted by my essay, that made an argument partly based on a link to a blog called “Niners Nation." I have enormous respect for Professor Pinker, and his description of me as “minor genius” made even my mother blush. But maybe on the question of subjects like quarterbacks, we should agree that our differences owe less to what can be found in the scientific literature than they do to what can be found on Google."
"Gladwell is right, of course, to privilege peer-reviewed articles over blogs. But sports is a topic in which any academic must answer to an army of statistics-savvy amateurs, and in this instance, I judged, the bloggers were correct."
And, yes, the bloggers *were* correct. They pointed out a huge, huge problem with the Berri/Simmons study. It ignored QBs who didn't play.
As you'd expect, the early draft choices got a lot more playing time than the later ones. Even disregarding seasons where they didn't play at all, and even *games* where they didn't play at all, the late choices were only involved in 1/4 as many plays as the early choices. Berri and Simmons don't think that's a problem. They argue -- as does Gladwell -- that we should just assume the guys who played less, or didn't play at all, are just as good as the guys who did play. We should just disregard the opinions of the coaches, who decided they weren't good enough.
That's silly, isn' t it? I mean, it's not logically impossible, but it defies common sense. At least you should need some evidence for it, instead of just blithely accepting it as a given.
And, in any case, there's an obvious, reasonable alternative model that doesn't force you to second-guess the professionals quite as much. That is: maybe early draft choices aren't taken because they're expected to be *better* superstars, but because they're expected to be *more likely* to be superstars.
Suppose there is a two-round draft, and a bunch of lottery tickets. Half the tickets have a 20% chance of winning $10, and the other half have a 5% chance of winning $10. If the scouts are good at identifying the better tickets, everyone will get a 20% ticket in the first round, and a 5% ticket in the second round.
Obviously, the first round is better than the second round. It has four times as many winners. But, just as obviously, if you look at only the tickets that win, they look equal -- they were worth $10 each.
Similarly for quarterbacks. Suppose, in the first round, you get 5 superstar quarterbacks and 5 good ones. In the last round, you get only one of each. By Berri's logic, the first round is no better than the last round! Because, the 10 guys from the first round had exactly the same aggregate statistics, per play, as the 2 guys from the last round.
I don't see why Gladwell doesn't get it, that the results are tainted by the selective sampling.
Anyway, others have written about this better than I have. Brian Burke, for instance, has a nice summary.
Also, Google "Berri Gladwell" for more of the debate.
The reason I bring this up now is that, a couple of days ago, Berri reiterated his findings on "Freakonomics":
"We should certainly expect that if [Andrew] Luck and [Robert] Griffin III are taken in the first few picks of the draft, they will get to play more than those taken later. But when we consider per-play performance (or when we control for the added playing time top picks receive), where a quarterback is drafted doesn’t seem to predict future performance."
What he's saying is that Andrew Luck, who is widely considered to be the best QB prospect in the world, is not likely to perform much better than a last-round QB pick, if only you gave that last pick some playing time.
Presumably, Berri would jump at the chance to trade Luck for two last-round picks. That's the logical consequence of what he's arguing.
Anyway, I actually hadn't looked at Berri's paper (.PDF) until a couple of days ago, when that Freakonomics post came out. Now that I've looked at the data, I see there are other arguments to be made. That is: even if, against your better judgment, you accept that the unknowns who never got to play are just as good as the ones who did ... well, even then, Berri and Simmons's data STILL don't show that late picks are as good as early picks.
I'll get into the details next post.
UPDATE: That next post, Part II, is here. Part III is here.