No one thought the Chiefs would go for it. Even CBS’ play predictor in the booth, Tony Romo, thought Kansas City wouldn’t snap the ball.
Backup quarterback Chad Henne was in the game. The Chiefs’ defense had stifled the Browns for most of the AFC divisional round. Kansas City led by five and just needed to keep Cleveland out of the end zone once more.
But there was the snap. Henne rolled to his right and fired to Tyreek Hill, who crossed the first-down line, effectively ending the contest. The Chiefs hadn’t just gone for it — they’d thrown.
It sounds more like a strategy that players of the Madden NFL video game series would employ than NFL coaches. But Andy Reid and the Chiefs are far from alone in their aggressiveness. In the 2020 regular season, NFL teams tried to convert on fourth down more than any season in NFL history. It marked three-straight years of record increases in fourth-down attempts.
For so many years, though, football has had a standard way of operating. Rarely have fourth downs featured conversion attempts. So for the fan at home or even many broadcasters, the mental wiring is a little off. It sometimes takes a little while to see why a team attempted to convert a particular fourth down. But the math, in most instances, backs up the growing NFL trend of fourth-down attempts.
We’re here to try and explain the math, to tear fourth-down decisions down to their smallest pieces and build them back up so that it makes perfect sense why coaches would choose to go for a first down rather than kicking or punting.
Modern football only has one distinct use for punting the football — sending it back to the other team on fourth down. NFL teams employ a specific player who specializes in this skill, and the best punters can send the ball booming 50 yards down field.
The decision to punt is often referred to as “flipping the field,” forcing the other team to start its possession half the field away from where it would’ve if a fourth-down conversion attempt failed. Teams with an especially strong defense might tend to punt more than others, because an offense could struggle to drive the length of the field against a dominant defensive unit.
Once a team gets inside the opponent’s 40-yard line, a field goal is in play. It’s an opportunity to “come away with points” at the end of a drive. A 50-yard field goal is attempted from about the 33-yard line — anything shorter than that is a relatively safe attempt for NFL kickers to add on three points, while only the top-notch kickers are very accurate from beyond 50 yards.
A field goal can often be used strategically to put a game out of reach. If a team leads by seven points with minimal time remaining, kicking a field goal makes it a 10-point game. The opposing team would then need two scoring drives to have a chance to win in what might be minimal time.
Go for it
If a team isn’t in a logical field position to kick and/or punt, or if there’s other contributing factors, it can leave the offense on the field and attempt to get a first down. Teams get four downs to make it the 10 yards required for the first down to continue the drive. It’s just risky to attempt to make it on fourth down, because if the offense comes up short, the opposing team gets the ball where the offense finished rather than where a punt may have placed them.
Teams are more likely to go-for-it on fourth down when down in close to the end zone where there’s a decent probability of a touchdown, on a short-yardage play when only a yard or two is needed to convert or when trailing, where giving the ball back to the other team isn’t really an option any longer.
Yardage to gain
The most simple thing for a team to consider is the yardage to gain for a first down (or a touchdown in a goal-to-go situation). It stands to reason that picking up one yard is usually simpler than picking up 10. The further from the first down marker, the harder it usually is to convert on fourth down.
Time and score
Whether a team wants to go for it on fourth down most strongly comes down to time and score. Each team views this factor differently, but the value of a given first down changes as the game goes on.
In a lot of ways, it’s a risk vs. reward equation. If a team is down 21 points, kicking a field goal from the 3-yard line doesn’t do much good, because a touchdown gives a much better chance of getting back into the game. If there’s only 30 seconds left and the losing team has the ball, there’s no time to do anything but for for it from midfield.
Teams have also begun to more often go for it on fourth down to put the game away, much like the Chiefs with Henne in the aforementioned example. By converting the fourth down, Kansas City all but guaranteed that Cleveland wouldn’t get a chance to win the game.
It also stands to reason that a time with more-skilled offensive players would have a better chance of making it on fourth down. That’s especially true if the offense has a couple of surefire fourth-down play calls to use that are tough to stop.
In 2020, the Bills and Dolphins both led the league with 80 percent conversion rates on fourth down. They each have skilled offensive players at every position. There are other very logical teams in the top-10, including the Saints (Drew Brees/Taysom Hill), Cardinals (Kyler Murray), Ravens (Lamar Jackson), Titans (Derrick Henry) and Packers (Aaron Rodgers).
Because it’s a small-sample size, an overall poor team like the Bengals ranked third in this statistic, but it’s also believable that Joe Burrow and Joe Mixon made things tough for defenses on fourth down.
To go or not to go, that is the question. Whether your mind knows it or not, the decision should essentially come down to win probability. “You play to win the game,” or something like that.
Win probability is a statistic that measures a team’s chances of winning the game based on historical data and the current game state. A team trailing 28-0 with 10 seconds left has a basically zero percent win probability, for example.
Each action that a team takes on the football field impacts the win probability. Go for it on fourth down and throw a touchdown? Chances of winning increase. Go for it on fourth down and throw a pick-six? Chances of winning decrease.
The numerous factors on a given decision is what makes it so tough — Is your punter good? How’s the other team’s offense against the defense? Where on the field are you? Is there time to make the comeback? Would a conversion put the other team away or give them a huge chance if it fails? Does a head coach increase his chances of getting fired based on the choice? The list goes on and on. So even though there’s historical data, it’s not a perfect science because each new situation is at least slightly different.
Midway through the season, NFL coaches were more and more confident in their decision on fourth-and-1, for example, and the results were supporting that call:
NFL points are up and there are assuredly several reasons why.
An obvious one: teams are going for it more often on 4th down (69% of the time on 4th-and-1)
A non-obvious one: teams have converted 4th-and-1’s at ridiculously high rates (77% so far in 2020) pic.twitter.com/uMoK4eodse
— Michael Lopez (@StatsbyLopez) October 6, 2020
Coaches don’t always get it right, though. In the conference championship round, Green Bay’s Matt LaFleur and Buffalo’s Sean McDermott both had their teams choose field goal in spots that a fourth-down conversion was shown to be the better call by Twitter accounts that do the math live. Neither of their teams advanced to the Super Bowl, not only because of those choices but not aided by them, to be sure.
To explain more concretely, let’s look at one of McDermott’s choices. The Bills trailed by 12 late in the first half in Kansas City. It was fourth-and-goal from the 2-yard line. McDermott chose to have Tyler Bass kick (and make) a short field goal to go into halftime down nine.
That’s despite Ben Baldwin’s fourth-down model showing that going for it and scoring a touchdown would increase win probability, and converting in that spot had more than a 50 percent chance. Buffalo’s win percentage if they didn’t convert would be 10 percent. A made field goal would make it 15 percent. But a touchdown would raise it all the way to 26 percent.
It was a heavy contrast to Reid’s decision to let his backup quarterback pass to preserve Kansas City’s quest for a repeat Super Bowl title, and it showed the ongoing battle between new-school thinking and old-school thinking. LaFleur and McDermott are both much younger coaches than Reid, yet they played it “by the book” while Reid trusted his players and the numbers to deliver.
Why do NFL teams go for it on fourth down?
There’s no way to give a cookie-cutter fourth-down example, because they’re all different. So understanding why a specific decision is being made in the moment is to comprehend the bigger picture.
Teams enter each game with the objective to win (Jaguars and Jets aside). Sometimes, keeping the ball and trying to cross the first-down marker gives a team the best chance to win. Occasionally, that’s just a gut feeling from the coaching staff and players, but usually the numbers back it up. Coaches still probably don’t go for it on fourth down as much as they should, but it’s trending up.
Once the postseason race heats up or the playoffs themselves come around, it’s not just about winning one game — it’s about winning the Super Bowl and hoisting the Lombardi Trophy. That makes some more aggressive and some more conservative, but it’s all with the same goal in mind.
The next time a time you’re watching goes for it on fourth down in a spot you didn’t expect, consider the ways it might have helped their chances of winning. Did it lead to more points? Did it keep the ball out of a star quarterback’s hands? Did it keep a drive going to grab back momentum or bleed the clock? Even if it fails, analytics is about trusting the process. Any choice can work once, but to win in the long run, a team wants the call that leads to victory most frequently.
Analytical football minds have been calling for years for coaches to go for it more on fourth down because yes, it raises the chances of winning. Coaches are just finally starting to really listen.