McCarthy's Critical Coaching Errors
The 2021 NFL season kicked off Thursday night in exciting fashion. The Super Bowl Champion Bucs picked up where they left off as Tom Brady orchestrated yet another game-winning drive. Much of the postgame conversation revolved around the poor execution of Dallas Cowboys kicker Greg Zuerlein. He was quick to accept responsibility as he told the press that, "If I do my job, we win this game."
While Zuerlein's humility is admirable, there are many different jobs that contribute to the outcomes of NFL games, not the least of which is making critical, in-game coaching decisions. Zuerlein did miss two field goals and an extra point, which makes it easy to point the finger at him with some simple arithmetic. When you lose a game by two points, those missed opportunities to score are glaring. It is helpful, however, to look at his kicking woes through the lens of game-winning chance (GWC) and compare that cost to that of Mike McCarthy's suboptimal fourth-down decisions.
In the table at the end of this article, we can see that the raw cost on fourth-down decisions, as evaluated by the EdjSports simulation model, totaled -8.6% GWC compared to the raw cost of missed kicks at -12.1%. Of course, the kicks were tangible and obvious errors to the viewers while the fourth downs were barely discussed by the television commentators. It is also worth noting that Zuerlein's successful 48-yard field goal improved the Cowboys' GWC by 10.2% when compared to the pre-snap GWC. According to the EdjSports play-calling model, he was expected to convert this field goal attempt 75% of the time. With this consideration, his net execution cost improves considerably. None of this absolves him from what was clearly a subpar performance, but the broader context represented in the table is important.
Redirecting the critical eye to Mike McCarthy reveals a fascinating decision on fourth-and-6 prior to Zuerlein's successful 48-yard field goal. It may seem surprising that an extensive custom simulation revealed this to be such a large error, at -5.8% GWC, but a few data points might help to tell the story.
- ~75% field goal success rate for Zuerlein (this is without any adjustment for the in-game performance)
- Historically an average NFL team would be expected to convert this fourth-and-6 about 45% of the time.
- With only one timeout remaining, a successful fourth-down conversion would ensure the Cowboys leave no time on the clock for Brady's attempt at a game-winning drive (~56% success rate) while improving the field position for the success of a later field goal attempt.
- A failed fourth-down conversion is devastating, but it does not completely seal the Cowboys' fate. With two timeouts they retain some residual GWC (perhaps 2% or 3%).
- There is also a slightly advantageous starting field position for the Bucs after a failed Cowboys field goal vs. a failed fourth down attempt.
Since we can debate actual success rates for both the field goal and the fourth-and-6 conversion attempt, let's look at some comparative model-generated GWC values for a range of assumptions that might argue in favor of the conservative action.
Additional assumptions for the Cowboys are:
Successful field goal = 44% GWC
Unsuccessful field goal = 2% GWC
Successful fourth-down attempt (exactly 6 yards) = 88% GWC
Unsuccessful fourth-down attempt (incompletion) = 3% GWC
For example, the calculation of GWC for a 75% field goal rate is the following parlay:
The most realistic values, which are supported by both simulations and empirical data, are indicated in bold. We can see that even shifting both field goal and fourth-down conversion assumptions by 5% in favor of the field goal attempt still doesn't quite overturn the model's recommendation of going for it.
Some additional considerations in favor of the fourth-down attempt are the conservative 6-yard advancement of the ball on a successful first down and Zuerlein's kicking woes. The strongest argument against the model's recommendation is the game-winning drive success rate for Tom Brady. We would need to drop Brady's game-winning drive rate to 48% with the assumptions of 75% field goal and 45% fourth-down to flip in support of a field goal attempt. While it is always difficult to anchor on any underlying assumption, it does seem compelling that the fourth-down attempt should have been strongly considered and likely would have produced significantly more wins on average. This may not get the monkey off Zuerlein's back in the coming days, but it does suggest he shouldn't shoulder all of the blame for a disappointing season opener.
|Qtr||Clock||Ball Position||Down||ToGo||Score||Play Choice||Decision Cost (GWC)*||Execution||Execution Cost (GWC)**|
|* Decision Cost represents the cost, if applicable, in GWC of the actual play choice vs. the optimal play choice assessed prior to the snap
** Execution Cost represents the cost, if applicable, between the pre-snap GWC (assuming actual play choice) and the updated GWC after the completion of the play.