Here’s a guest post from Eric Fingerhut, published with love for the Washington Post, Neil Greenberg and statistical analysis.
“Stats show that Redskins’ Robert Griffin III will never be as good as his rookie season,” screamed the headline on the Washington Post’s Fancy Stats blog Monday afternoon. The third sentence of the blog post was less emphatic but still pretty definitive: “We likely have seen the best RGIII will ever be.”
There are a number of reasons I could think of why RGIII may end up never flashing the form we saw in 2012: lingering effects of his knee injury, a failure to adjust to being a pocket passer, defenses simply figuring him out. But stats that show that RGIII will never be the same, even two, three or five years from now? I’d be interested in seeing those. But the author of the post, Neil Greenberg, actually shows no such thing.
Using a statistic called “adjusted yards per attempt” — basically dividing a QB’s passing yards by his attempts while also taking into account touchdowns and interceptions — he first shows that, other than Griffin, just three rookie quarterbacks since 1970 have achieved an AYPA of 20 percent above league average. Only one of those quarterbacks had a season as good as that again, which would give Griffin a 33-percent chance of returning to form, slightly better than never. (That one QB who did get back to that level? Dan Marino, who did it five more times.) Of course, as anyone who knows anything about statistics should know, drawing inferences from a sample size of three is pretty unreliable.
So Greenberg then links to a list of all QBs who ever had a season 20 percent above the league’s AYPA average. Conveniently, there are exactly 100 on the list, 47 of which had at least one more such season during their career (including such illustrious names as Chris Chandler, Elvis Grbac, Erik Kramer and Wade Wilson). Meanwhile, somewhat confusingly, the post also contains a graph which states that 49 percent of QBs who hit the 20 percent over AYPA average never repeat that achievement.
In other words, a post with a headline stating that RGIII will “never” be as good as 2012, and whose text claims that we’ve “likely” seen the best of RGIII, actually shows that RGIII has about a 50-percent chance of being as good as he was in his rookie season. Sure, 50 percent isn’t a guarantee, but it’s a very long way from never. And if someone tells me that something is “likely,” I usually think there’s a much better chance than 50 percent of it happening.