This was one of the most gutsy moves of the season, one that wasn't called by head coach Mike McCoy or special teams coach Kevin Spencer, but it was called by Weddle himself. Luckily for them, it worked... or was it luck?
Should Weddle have audibled to the run? What success rate did he need to make it worth it?
The Situation
In order to figure out whether or not it was the right move, we need to look at the situation as a whole. Some of the factors we have to look at include, the time left in the game, the current down and distance, and the win probabilities when either a) Converting 4th down b) Failing to convert 4th down and c) Punting.
From these numbers, we will be able to figure out what chance of success the Chargers will need on this play to attempt to gain the 1st down rather than punt.
From these numbers, we will be able to figure out what chance of success the Chargers will need on this play to attempt to gain the 1st down rather than punt.
The Clock
It's early in overtime, so the time on clock doesn't really factor in this case. However, what does matter is that it's overtime. If a play goes bad here, there's no turning back as Kansas City would have excellent field position for a win. Many coaches take the opposite approach, refusing to be aggressive early in the game when a mistake can be overcome since there's a lot of time left in the game.
The Down and Distance
Though the graphics on the screen, and the official play-by-play, listed the play as a 4th and 2 from the 28 yard line, the ball was actually spotted on the 27 yard line, making it a 4th and 3 play, as shown below.
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| The famous fake punt play, actually 4th down and 3 yards to go |
The fact that it's 4th and 3 will obviously make it more difficult to convert into a 1st down than 4th & 2, however running a fake gives the Chargers the element of surprise.
Win Probability When Converting, Failing, or Punting
The Win Probability for the Chargers when converting, failing to convert, or punting will help us determine what the risk is of going for it, and what the proper decision should be. We will use the Win Probability Calculator at Advanced NFL Stats.com to give us a good estimate.
We don't necessarily know the exact situation after the play is run, but let's make the following assumptions
- A successful conversion leaves the Chargers at their own 31 yard line (just past the 1st down)
- A failed conversion leaves the Chiefs with possession at the Chargers' 29 yard line (just short of the first down)
- A Mike Scifers punt (net average 40 yards) would leave the Chiefs on their own 33 yard line.
A Successful 4th Down Conversion
Not worrying about HOW the Chargers convert this 4th down yet, if they gain a 1st down on their own 31 yard line with about 12:45 left to go in the first possession of overtime gives them a 56% chance of winning the game. While better than a 50/50 chance of winning, but is also reliant on them converting the 4th down first. Is this risk worth it? We'll have to see what the actual chance of converting needs to be for this to be worth it.
A Failed 4th Down Conversion
Though the Chargers gained the first possession in overtime, if they fail to score on this drive, the next score wins the game according to overtime rules. A failure to convert here would be disastrous, as the Chiefs would now gain the ball with great field position, but also be in a position to win outright with any score. Even if they didn't gain any more yardage, the Chiefs could attempt to win the game with a 47 yard field goal attempt. Not an automatic field goal, but a good enough starting point that the Chargers would hate to turn the ball over.
According to the WP calculator, if the Chiefs gain the ball at the Chargers 29 yard line with 12:45 left in overtime, the Chiefs would have an 82% chance to win the game. From the Chargers' perspective, they would have a scant 18% chance of winning if they failed in this spot.
Punting
Assuming the Chiefs return a punt to their own 33 yard line with 12:45 left to go, the Chiefs would have a win probability of 59%, leaving the Chargers with a 41% chance of winning. Certainly better than the 18% chance of winning if they turned the ball over on a failed 4th down conversion.
The Calculations
When deciding whether to punt or go for it here, we have to look at the combined probabilities of success and failure when going for it. If the combined probability of winning is greater than the probability of winning when punting, then the Chargers should go for it.
In order to go for it, the following inequality must be met:
WP(Go for It) > WP (Punt)
P(Conversion)*WP(Conversion Success) + P(Failure)*WP(Failure) > WP(Punt)
The probability of failure on a 4th down conversion is simply 100% - the probability of success, and we can substitute the numbers we found earlier for the Win Probabilities and we will simplify our inequality as follows:
P(Conversion)*(.56) + (1-P(Conversion))*(.18) > (.41)
I'll substitute x for P(Conversion) to make it easier to read, then do some math operations to simplify the best we can.
x(.56) + (1-x)(.18) > (.41)
Multiplying (1-x) by .18
.56x + .18 - .18x > .41
Combining like terms on the left side of the inequality
.38x + .18 > .41
Subtracting .18 from both sides
.38x > .23
Finally, dividing both sides by .38 gives the final inequality
x > .605
The Conclusion
In order for going for it to be right, the Chargers must convert this 4th down over 60.5% of the time. So was this the right decision?
The average team converts a 4th & 3 at a 57% rate league wide, so on its face value, it is not something that should have been attempted. However, this is not a normal 4th & 3 situation. The Chargers lined up in punt formation, instead of a regular offensive formation, which meant the Chiefs would not have been as prepared to stop a play. Also, Weddle was given the go ahead during game planning to audible to the run if he felt the chances of success were good.
In this specific situation, he looked at the Chiefs' defensive formation, made a gut decision (probably figuring a greater than 60% chance of succeeding) and made the call.
In this specific situation, he looked at the Chiefs' defensive formation, made a gut decision (probably figuring a greater than 60% chance of succeeding) and made the call.
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| Eric Weddle (32), sees 7 Charger blockers vs. 6 Chiefs defenders, and a gap off of the left guard |
Weddle made the call, took the direct snap and reached the line to gain before the officials ruled stoppage of forward progress, ending the play. Weddle actually fumbled a split second afterwards, leading to what might have appeared to be a Cyrus Gray fumble return for a touchdown. Incidentally, at the end of the play, an incredulous Gray takes his helmet off on the field of play, which could have drawn a 15 yard unsportsmanlike conduct penalty which went unenforced.
The calculated gamble worked, Weddle is a genius, and the Chargers go on to win. If the gamble had failed to work, then Weddle probably would have been called insane and the Chargers would have likely lost. However, as long as the chance of making the 1st down was greater than 60.5%, it was the right move.
The hard part in this case isn't necessarily the math, but properly estimating the actual chances of success. This number surely was buried right inside of Eric Weddle's gut. That's ultimately what makes the difference between genius and insanity.
The calculated gamble worked, Weddle is a genius, and the Chargers go on to win. If the gamble had failed to work, then Weddle probably would have been called insane and the Chargers would have likely lost. However, as long as the chance of making the 1st down was greater than 60.5%, it was the right move.
The hard part in this case isn't necessarily the math, but properly estimating the actual chances of success. This number surely was buried right inside of Eric Weddle's gut. That's ultimately what makes the difference between genius and insanity.
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