According to an exhaustive study of NFL play data conducted by Yale professor Cade Massey, what happens on first and 10 in an NFL game is a powerful indicator of who will win.
According to Dr. Massey, an assistant professor at the Yale School of Management, the ability of an NFL team to meet certain benchmarks on each down is one of the best predictors of whether a drive will be successful. When it comes to first down, he says, the magic number is four. That’s the number of yards Mr. Massey says teams need to gain on first and 10. Those that do, he says, are more likely to be successful in making a first down and keeping the drive alive.
. . . The four teams in Sunday’s playoffs have different approaches to first down—and rates of success. The Pittsburgh Steelers, who play the New York Jets Sunday for the AFC title, run the ball 55% of the time on first and 10 in the first three quarters of a game. (The fourth quarter isn’t included in the calculation because play-calling can be largely dictated by whether a team is ahead or behind). These runs by the Steelers rarely catch the opposing defense by surprise. . . [T]he Steelers are daring the opposing team to try to beat them in a head-on collision.
. . . The Steelers have only managed to attain that magic mark of four yards or more on first downs 48% of the time—a number that puts them in the bottom half of the NFL. So far, the Steelers have been able to compensate for their lack of success on first downs by connecting on long passes on other downs. They’ve also excelled in the reverse role: Pittsburgh’s defense is the best in the league on first downs, holding opposing teams to less than four yards about 59% of the time.
. . . According to the numbers, the Jets are similar to the Steelers in that their first-down defense is better than their first-down offense. . . .
The Green Bay Packers rank No 2. in the NFL this season in recording successful plays on first and 10. The team also likes to pass on that down and distance 54% of the time—more than any other team in the playoffs and all but four in the NFL.
When Green Bay played the Atlanta Falcons in the divisional round of the playoffs, the Packers managed to run successfully on first and 10 early in the game with running back James Starks. But later in the game they began lining up in running formations—sometimes with two tight ends—and instead running play action passing plays. Those plays faked out the Falcons and led to big gains.
So who is likely to prevail? Green Bay is by far the best first-and-10 team left in the playoffs. But their opponents, the Chicago Bears, are also one of the best defenses at stopping offenses in that situation. . . .
Read the rest here. This is not a shocking result, but it’s possible to draw the wrong conclusion. I think the wrong answer is to pick plays that have extremely low variance at the expense of expected gain — i.e. the plunge into the line that, while it rarely loses yards, doesn’t average much, with the thought that you just want to avoid negative plays and want to get close to that four yard gain. As the chart below indicates, your probability of getting a first down in three plays depends far more on your expected gain than it does the variance.
And, of course, game theory is relevant because you might significantly improve both your expected gain and variance on first down with simple consistent gainers, like runs off tackle, quick passes, and so on, by taking high variance chances, like play-action or some other kind of play that can significantly keep the defense off balance.
All that said, I think the upshot of Dr. Massey’s analysis is that most first down playcalling is not good, and too often puts the offense in a bad spot. If you show me a team that is good on first down, I’ll show you a good offense. Indeed, the best offenses look at it like they are playing under Canadian rules: if you only have two downs to get a first down, you approach the problem quite a bit differently. Third down shifts the burden away from the defense to the offense; better to avoid as many third downs as possible.