Each week, we’ll highlight a few of the most important coaching decisions that contributed heavily to the final result. While many of these high leverage situations occur on fourth down, we’ll introduce some other situations where a coaching decision swung his team’s chances of winning in a major way as the season goes on.
There are a few main tools for doing this analysis: The most obvious is win probability, which takes into account the situational components of the game along with the strength of each team in each facet to predict the chance of winning. Another data point that is useful and in most cases aligned with win probability is expected points, which takes into account the field position, down and distance to predict the number of points that we expect the offense to score on the next offensive play. We can also compare the expected points for a team before and after a play to measure how successful a play was. We’ll also make use of conversion probability, which leverages the strength of each team in each facet to predict the chance a team picks up a first down on a given play.
During the season, more analysis may work its way into this column, but this gives us plenty to start with. While we leverage machine learning to make sound predictions for each of the above, we will do our best to make this article accessible to all and we’ll do our best to answer any questions.
Ravens going for two down 11 with 12:27 left in the game
The Baltimore Ravens, down by 17 points on the road to the 2-0 Kansas City Chiefs, scored a touchdown on a one-yard run by Mark Ingram after an extremely unlikely conversion of a fourth down by Lamar Jackson and Seth Roberts.
Down 11 points, John Harbaugh opted to go for two points and was unsuccessful. Unlike their attempt after a first-quarter touchdown, this try was not elicited by a pre-snap penalty by the Chiefs. They went for it because of the math. Qualitatively, going for two points on the first in a sequence of potential scores means that you know what you need to win or tie a game on subsequent scores and can plan accordingly. For example, had the Ravens converted the two-point conversion, they know a priori that scoring a field goal and a touchdown with a conventional PAT with the game outright, instead of leaving similar decisions to the end of the game. Mathematically:
After missing the two-point conversion attempt: KC: 94.3% to win, BAL 5.7%
If they made the two-point conversion attempt: KC 89.1% to win, BAL 10.9%
If they would have kicked the PAT: KC 92.8% to win, BAL 7.2%
Hence, the benefit of making the two-point conversion over kicking the PAT was 3.7% win probability points, while the loss via missing the two-point conversion over kicking the PAT was just 1.5%. Assuming the Ravens are a modest 50% on two-point conversions, this is easily the preferable decision. In fact, it would only cease being the preferable decision if the Ravens were under 41% making two-point conversions, a futility that would not be expected with a quarterback like Jackson and the Ravens' offense we would give a 57% chance of converting.
Tampa Bay opt for field goal attempt 4th-and-2 on New York's five-yard line leading 28-25 with six minutes left to play
After seeing an 18-point halftime lead cut to three points, the Tampa Bay Buccaneers found themselves 13 yards away from the Giants’ end zone, preparing for a 1st-and-10 in the middle of the fourth quarter. A touchdown wouldn’t immediately end the game, but it would put the game-winning chance at roughly 95%. Bruce Arians and Byron Leftwich, however, decided to go the conservative way, calling three runs in a row. Those gained a combined eight yards, putting them in the following situation: 4th-and-2 at the opponent’s five-yard line with six minutes left to play in the fourth quarter while leading 28-25. Almost any fourth down with two or fewer yards to go should be a relatively easy decision, but the key on this one is leading by three points. There is the saying that leading by three late in the game is better than leading by six because your opponent will play for overtime in the first scenario, but for the win in the second scenario. This game was a prime anecdote: The Bucs opted to kick a field goal to go up 31-25 and after both teams shared punts, the Giants faced a do-or-die drive in which they ultimately maneuvered themselves in a 4th-and-5 situation near the goal line. Down by three, it’s safe to say they would have tried to tie the game with a short field goal, playing for overtime. Down by six, however, they went for it and Daniel Jones was never touched on his way to the end zone on a quarterback draw, giving the Giants a one-point lead.
Mathematically this translates as follows: Attempting a field goal in this situation gives the Bucs an 81.2% chance of winning the game, while a turnover on downs would have reduced their chances only by 5.6%: They still would have won the game 75.6% of the time. If they convert on fourth down, they win the game 93.2% of the time, increasing their chances by 12.0% compared to kicking the field goal. Their chances to convert a potential fourth-down attempt were 54.9% by our model. That incorporates not only the game situation but also the respective unit strengths. This leaves us yet again with a situation we have pointed out before: The potential gain is significantly greater than the potential loss, and the chance of conversion is greater than a coin flip. Not going for it means the Bucs were gifting their opponent a 4.1% better chance to complete the second-half comeback. What makes the decision even more puzzling and a testament of inconsistent (and thus arbitrary) decision making: Bruce Arians said he thought his kicker Matt Gay was better at long field goals than at short field goals, which is why he called his offense to commit an intentional delay of game penalty before the attempt at a game-winning field goal at the end of regulation. The idea that your kicker is worse at easier field goals isn’t very convincing to begin with, but if we take it for face value for the matter of our decision evaluation, it should have shifted the decision even more towards keeping the offense on the field on fourth down.