When Playing It Safe Backfires: Analyzing the Patriots’ Final Drive Decision-Making

by Andrew Mooney

Here’s a look inside the final sequence of Sunday’s wild 20-18 loss to the Cardinals. For my numbers, I’m making use of the Win Probability Calculator made available by advancednflstats.com. Specifically, I’ll be investigating the Patriots’ decision to settle for a 42-yard field goal at the end of regulation rather than attempting to improve their field position.

Game situation: 1st-and-15 at the Cardinals’ 23-yard line, 00:46 remaining in the 4th quarter

At this point, things are looking awfully fortunate for the Patriots. They just recovered a miracle fumble, and though a couple of Gronk malfunctions (a holding penalty that nullified a touchdown and a false start) may have cost them a sure victory, they still hold a 76 percent chance of winning the game. Their expected points value here is +3.56, meaning that teams score touchdowns more often than field goals in this scenario. However, the Pats elect to take the conservative route, with Tom Brady centering the ball in the middle of the field, sustaining a one-yard loss on the play. The clock winds down to seven seconds before Brady spikes the ball to stop it.

Game situation: 3rd-and-16 at the Cardinals’ 24-yard line, 00:07 remaining in the 4th quarter

The game will be decided by a Stephen Gostkowski field goal attempt. According to a separate bit of research from Advanced NFL Stats, kickers convert from this distance just under 80 percent of the time. The Win Probability Calculator concurs with this figure, giving the Patriots a 78 percent chance of victory—still comfortably in their favor and slightly higher than before, but not significantly so. Gostkowski misses the ensuing field goal try, and the Patriots lose a shocker.

Now let’s imagine a scenario in which the Pats continue their drive toward the end zone. Forty-six seconds is enough time within which to run two plays, and taking the Patriots’ average yards per play for the game (5.0), let’s assume they gained an additional ten yards before spiking the ball with seven seconds left.

Hypothetical game situation: 4th-and-5 at the Cardinals’ 13-yard line, 00:07 remaining in the 4th quarter

This is chip shot distance. From this range, kickers successfully make field goals about 90 percent of the time, again coinciding with the Win Probability Calculator’s figures, which give the Patriots an 86 percent chance of winning—a better outcome than the scenario in which they ultimately placed themselves.

The main takeaway here is not that the Patriots sacrificed exactly 0.08 points of Win Probability by playing it safe, but rather that a 42-yard field goal is far from a sure thing. Why settle for it when you have an incredibly competent quarterback—one with a miniscule 2.1 percent career interception rate, I might add—who’s more than capable of pushing the result closer to “sure thing”? A slide into the middle of the field is hardly the optimal use of Brady’s talents.

This post can also be seen on Boston.com here.

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2 Responses to When Playing It Safe Backfires: Analyzing the Patriots’ Final Drive Decision-Making

  1. Jeff says:

    Interesting data but it is not as clear cut as you make your conclusion sound. The fact is that the Pats increased their win probability from 76% to 78% by playing it conservative. This is an improvement! Your 86% is totally misleading since it assumes 5 yards per play and assigns a 100% probability to this. You then point out that Brady is an above-average QB (which presumably the Win Probability Calculator does not take into account) and use the 2.1% interception rate to imply that the risks are low, but what about other risks like a fumble or a sack or a penalty. The Pats had 8 penalties on 78 plays run, so the penalty risk is substantial. I will grant you the above-average NE offense probably improves their odds very slightly and of course Brady could have tried a more conservative form of aggressiveness (e.g. throwing the ball away quickly if there was not an easy completion available). But you didn’t make any attempt to recalculate the odds using these factors so I don’t know how you can come to the conclusion you do. Also the NE offense had not played above-average in the game to that point, so I’m not even sure how much credit you can give them for this. My overall conclusion from the data above is that all the criticism NE got for playing it conservative isn’t fully warranted and that it is was something close to a toss-up odds wise.

    • Good call. The ten yards gained may have been an average outcome, but depending on the distribution of yards gained, there could very well be a less-than 50% chance of getting 10-or-more yards. Include, as you say, the chance for penalties and turnovers, and getting 10-or-more-yards in two plays might only happen 25-30% of the time.

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