Which teams got it right on fourth-down and 2-point conversion calls in Week 8 of the 2021 NFL season -- and which teams got it wrong? The Next Gen Stats analytics team uses the Next Gen Stats Decision Guide powered by AWS to break down the numbers behind the decisions that shaped the game.
Packers get a boost from Matt LaFleur's red-zone aggressiveness
LaFleur and the Packers faced four fourth-down decisions inside the Cardinals' 15-yard line on Thursday, with the NGS Decision Guide recommending that they go for it -- instead of kicking a field goal -- in all four scenarios, by the difference of at least 2 percentage points. LaFleur correctly kept the offense on the field in three of the four instances, and taking all four decisions into account, he increased the team's chances of winning by 11.8 net percentage points (setting aside the outcome). The offense converted on two of the three tries.
Of the four aforementioned fourth-down calls, the most obvious go for it situation was the only one in which the offense failed to convert. Green Bay had a 72 percent chance of converting here -- although we should note the conversion chances were higher with a run play (76%) than with a pass (63%). One could say the decision to call a pass play out of shotgun formation significantly reduced the surplus value of the go-for-it decision.
Either way, factoring in situation and score, going for a two-score lead -- rather than a six-point advantage via a high-probability (98%) field-goal try -- was the optimal decision by 10.7 percentage points in expected win-probability value. Yes, the Packers failed to convert, but we're here to celebrate the process over the outcome. And thanks to a heads-up interception by Rasul Douglas in the end zone on the ensuing Cardinals possession, the Packers still got the result they wanted in this high-stakes prime-time NFC showdown.
Frank Reich sets the tone for Indy early
In this key AFC South matchup, Reich and the Colts went for it on fourth down three times in the first quarter, and the NGS Decision Guide agreed with all three decisions by 0.5, 3.5 and 1.2 percentage points in expected win-probability value, respectively. Indianapolis successfully converted on two of those attempts, helping the team establish a 14-point lead through the first quarter of action. And though this game eventually ended in heartbreak for the Colts, it wasn't due to a tentative approach on fourth down.
The Colts had already converted on a fourth-and-3 situation earlier in the drive, and Reich was not going to pass up the opportunity to finish with a touchdown. Per the NGS Decision Guide, going for it was worth 3.5 percentage points more in expected win-probability value than kicking a field goal -- in fact, a successful field-goal attempt would have dropped the Colts' win-probability from 64 percent to 62 percent, while a successful offensive play (resulting in a touchdown) would have boosted the team's chances of winning to 72 percent. Even measured against the probability of completing a chip-shot field-goal try (98%), the potential reward made going for it worth the risk.
FIRST QUARTER: With 2:59 remaining and the Colts (leading 14-0) facing a fourth-and-3 from the Titans' 40-yard line, Wentz throws an incomplete pass to Pittman.
The play design complicates the picture of this decision. The NGS Decision Guide marked this as a slight go-for-it situation -- that is, where the difference between going for it and kicking is between 1 and 2 percentage points in expected win value -- with the margin here being 1.2 percentage points. But that figure is based on a 49 percent likelihood of converting. The 17-yard throw to Pittman, on the other hand, had a 42.5 percent chance of being successful, according to our completion probability model, meaning it was a less optimal call than the decision to go for it on its own.
Matt Rhule and Arthur Smith keep both teams conservative
In a game with three times as many field goals made (six) as there were touchdowns scored (two), the Panthers' Rhule and the Falcons' Smith consistently avoided going for it on fourth down. The two coaches combined to face eight opportunities where the NGS Decision Guide recommended going for it by any margin, and they kicked seven times (the Panthers kicked all four times and the Falcons kicked three times while going for it once). When it comes to win-probability lost, Rhule and the Panthers (6.3 percentage points) lost more than Smith and the Falcons (2.2 percentage points) as a result of their suboptimal decisions.
Let's take a closer look at the one decision either coach got correct, according to the NGS Decision Guide:
SECOND QUARTER: With 5:33 remaining and the Falcons (leading 10-6) facing a fourth-and-1 from the Panthers' 45-yard line, Matt Ryan completes a 1-yard pass to Cordarrelle Patterson for the conversion.
The guide also happened to peg this call as the most obvious go-for-it decision on the board, with 2.7 percentage points of win-probability value. Fourth-and-1 in "no man's land" is a situation where most coaches feel comfortable keeping the offense on the field. The Falcons had a 72 percent chance of converting the first down, and their win-probability increased to 73 percent following the successful conversion.
Atlanta declined to go for it on two other fourth-and-shorts in the first half, with both those plays coming inside the Falcons' own 30-yard line. While the guide found value in going for it in both situations, doing so deep in one's own territory is still an unconventional decision, and the confidence in those decisions were based on factors of less than 1.3 percentage points in expected win-probability value.