By Santiago Casanova (@BRotoFFCasanova)
NOTE: Santiago has an app that is part of a series of Fantasy Football tools to make decisions about who to line up and who to sit in your weekly lineup, advanced statistics, rankings and articles. Download it here
Decisions of when to gamble on fourth down in the NFL they’re a hotly debated topic by fans, analysts, and league executives alike. Everyone has their own idea of when it is appropriate and when it is too risky, but what do the numbers say about it?
The decision-making model in the NFL
It is likely that you have seen a graph on TV or an analyst say that this or that is the correct decision in that situation, but first you have to understand how you get that conclusion.
The first step in building a fourth-down decision model is actually building another model: the probability of victory. To know if it is better to gamble or kick we need to analyze how it will affect the game. This model takes into account many variables such as: the quarter, the time left, the betting odds before the game, the timeouts for each team, the chances of scoring points on this drive, etc.
With these and many other variables it is possible to calculate the probability that a team has of winning the game at any moment and, therefore, the probability that they would have after a certain action.
When it comes time to decide, the model analyzes the following scenarios:
- probability of victory right now
- probability of victory if they play it and they DO NOT reach the first and ten
- probability of victory if they play it and YES they reach the first and ten
- probability of victory if they kick a field goal and score it
- probability of victory if they kick a field goal and miss it
- probability of victory if they punts to return the ball to the other team
In addition, you also have to calculate the probability of these things happening. It is not the same to gamble on fourth and 1, than fourth and 13. The final decision is made as follows:
% win if failed + (% win if achieved -% win if failed) * (probability of succeeding)
For both field goals and gambling, the number that comes out higher in that equation is the decision recommended by the model.
Some examples of crucial decisions in the NFL
Last week it was the decision of the coach of the Chargers, Brandon Staley, play it in fourth and one in his own 19 yard !!
Brandon Staley goes for it on 4th & 1 at own 19 yard line. This is what happens when NFL media start anointing coaches “brilliant” who haven’t done shyt in the NFL yet. pic.twitter.com/hQKpMqHoHi
— ChuckModi (@ChuckModi1) October 17, 2021
In this case, the Chargers were losing by 18 points and their probability of victory was already very low. So low, in fact, that if they failed the conversion (as happened in the game), they had the same probability of winning as if they made a punt. The explanation is the following:
We can see that the probability of converting this fourth and 3 is low (44%) but the percentage of victory is much higher if it is converted than if a field goal is scored. Ultimately, trying to gamble, regardless of whether he converts or not, is the decision that maximizes the Chargers’ chances of winning. Therefore, no matter what the author of the tweet that we quote to see the play, the analytics show that gambling it was the right decision for the head coach. Another thing is that it is realized by the execution of those responsible (players).
Another situation much seen and discussed on this same model was that of the game on Monday night. Where Josh Allen and the Bills played it (and they missed) instead of tying the game with a field goal.
The idea behind this is that if they tie, the game is very likely to go into overtime and, under current NFL rules, the team that wins the toss has a very high chance of winning. On the other hand, if they play it in the goal zone it is theoretically very likely that they will score with very little time on the clock and ultimately win the game.
These two are just a few of many cases where the decision that was made was correct, but the result did not favor the process. It is much easier to criticize the result once you know where the play ended, and more so when it fails, but you have to understand that the coach’s job during the game is to make the most informed and accurate decisions possible.
