In 2011, the New York Mets' most reliable slugger—career-.300-hitting David Wright—had a miserable season. At an age when most players reach their prime, Wright batted just .254 with 14 home runs. This year, he has returned to form and then some: He's second in the National League with a .370 average and leads the league with an OPS+ of 190. As a Mets fan, I'm thrilled he's playing so well. But as a Mets fan, I'm also a little pissed off.
Does Wright have a new approach at the plate, or could something else explain his recent resurgence? Maybe it's that Wright happens to be in the last season of a six-year, $55 million contract. With his finances in the lurch—the Mets must decide whether to keep him for 2013—he stands to gain more than ever from having an incredible "comeback" season. He has a financial incentive to train harder, play harder, and hit the ball harder than he did last year.
Mets fans caught a whiff of opportunism last year, too, when All-Star shortstop Jose Reyes—28 years old, in the twilight of a his own contract—had his best season ever. He left the team for a payout in Miami, and his numbers promptly dropped off by 40 percent. And the Cardinals front office watched Albert Pujols, perhaps the best hitter in baseball, grab a $240 million, 10-year contract with the Angels this past off-season. As the ink of his signature dries, Pujols limps along with a .238 batting average and a slugging percentage of .406.
This tendency, real or imagined, for players to amp up their effort for a new contract and then start dogging it the year after has the distinction of being at once incredibly obvious (athletes turn it up when it counts!) and deeply counterintuitive (athletes always give 110 percent!). Of course David Wright puts in some extra effort with his livelihood on the line. Of course he plays as hard as he can every game. Which is it?
"The obvious answer," wrote Malcolm Gladwell in a 2006 discussion of the contract-year phenomenon with ESPN's Bill Simmons, "is that effort plays a much larger role in athletic performance than we care to admit." Problem is, no one knows if that's true. Once you get past the most salient anecdotes—David Wright for me, Erick Dampier for Gladwell—it becomes nearly impossible to discern whether professional athletes have a genuine tendency to turn it up in their contract years (or to goof off the year after). Sports economists and freelance statheads have gone at this question for decades, and their results—presented in peer-reviewed journals, conference talks, and plenty of undergraduate theses—haven't yet produced a reliable answer.
All these studies face the same fundamental problem: To figure out whether players tend to do better or worse in a given year of their contracts, they first need to determine how well a player should perform. In other words, they have to guess what David Wright would be expected to do in his 2012 season, given everything else we know about him, and then compare that guess to his actual performance. That's a tricky task, and one beset by confounding correlations. For one thing, an athlete's output has a lot to do with his age: A player might improve his stats through his late 20s, and then start to decline as he reached his mid-30s. By the time David Wright gets to the end of his next contract, he'll be a creaky 35 or 36—a point of his career where most guys are barely producing at all. In that case, Wright would be overperforming just by keeping his numbers out of the gutter.
There are other confounds, too. Players who do well in their contract years tend to sign long-term deals. They also tend to play a little bit worse in the following year, as their performance regresses to the mean. Meanwhile, guys who blow it in their contract years are more likely to end up washing out of the league or signing a short-term deal. Any analysis must take all these variables into account before it can start guessing how anyone "should" perform in his contract year or the one after. And even the most thorough models can introduce subtle distortions that tilt the results.