## Should the Vikings Have Punted?

The Vikings were one touchdown away from what would have been a stunning upset of the undefeated Packers. MIN began the drive at their own 2 with 5:26 to play. They managed to make it out the their own 36, but with 2:37 to play they faced a 4th and 10. With all three time outs remaining, Leslie Frasier elected to punt. Was this the best decision?

It's a very close call.

Converting a 4th and 10 is a 35% proposition. And had MIN converted, they would have had a 1st and 10 at their own 46 (at least) with about 2:30 to play. That equates to a 35% WP. On the go-for-it side of the ledger, having all 3 timeouts isn't beneficial because they had plenty of time to score, even without them. Time was not the factor.

A failed conversion attempt gives them an almost zero chance of winning. So on net, the go-for-it option is just:

0.35 * 0.35 = 12.2% WP

A punt would be expected to hand GB possession at their own 26 or so, worth 0.13 WP. But this is where the 3 timeouts might make a difference. But adjusting for the one additional timeout than typical in this situation doesn't affect the numbers much because the factor driving the WP isn't time as much as whether or not MIN can make a stop on GB's initial series. Still, it tips the balance in favor of the punt, giving it a 0.14 WP. Then again, GB's offense isn't typical, so there should be consideration given to keeping the ball out of their hands all together.

The numbers are likely even closer, given the assumption that a successful conversion gains exactly 10 yards. Plus, although a failed 4th down conversion attempt yields an almost certain loss, the WP must be something a tiny bit larger than zero.

When the league baseline numbers are this close, it's hard to fault either decision. Coaches are expected to have local information specific to the situation that might edge the choice one way or another. (I said expected to, ok?)

One thing to note is that this kind of decision should be made at least before 3rd down. If you have a 4-down mindset, you have many more options on 3rd down. In this case, MIN wouldn't need all 10 yards. They could check down or scramble to pick up a handful of yards, then come back on 4th down to get the conversion. As long as you think you can get 3 or more yards, making the 4th down conversion attempt significantly more manageable, it makes it worthwhile.

### 6 Responses to “Should the Vikings Have Punted?”

1. Keith Goldner says:

Great stuff. What added to this is the fact that GB is pretty poor running the ball and MIN has been solid stopping the run game. The qualifier is that MIN is giving the ball back to a non-typical offense. GB is definitely not normal; they have the largest difference (by far) between Run EPA/P and Pass EPA/P (0.47 - predominantly due to their ridiculous passing efficiency).

That being said, I'd be curious to what Frazier anticipated would happen. I would guess that due to the Packers' soft run game and the fact that standard operating procedure in the NFL is to run the ball 3 times and punt if you don't convert, Frazier believed they could easily stop the run and get the ball back. If he was worried the Packers would try to convert through the air, there would be no reason for the Vikings to punt given the high probability of the Packers converting with the pass game.

If my gut feeling above is right, then Frazier was right. The Packers only ran the ball the rest of the game. Unfortunately, they ran it down the Vikings' throats.

2. Jonathan says:

A large % of Green Bay's runs happen in favorable endgame situations, where the defense is expecting a run. Grant/Starks combine for 0.53 WPA.

So I would argue that their run game is actually decent. Unless they are racking up all of their WPA on made-to-order screen passes.

3. Jeff Clarke says:

I'm sort of surprised to read the last paragraph. I've always been highly suspicious of the "You have two downs to convert....Just try to make it fourth and manageable" mindset.

Its hard to calculate the math behind it because teams could go for the whole 10 yards and end up with less or they could go for less and end up with the whole 10.

Still, I tend to view this argument as similar to the sacrifice bunt in baseball that can be mathematically proven to be a bad idea in the vast majority of the times its tried.

Here is the way I look at it. The probability of getting 10 yards when you need 10 yards is 35%. So if you tried to get the whole 10 on both downs, your overall probability would be 35% (get it on 3rd) + 65%*35%=22.75% (fail on 3rd---get it on 4th). So if you try to get the whole thing on both downs, your overall prob is 57.75%.

If you can cut it to 3 yards, you have about a 55% chance of getting it on 4th so your actual probability of overall success has gone down after a "successful" 7 yard third down play. Of course, thats assuming that you got the 7 yards on 3rd down. Getting 7 yards isn't that much easier than getting 10 yards.

The bottom line is that I believe the whole "3rd and manageable/4th and manageable" thing is just one more example of compilation bias and overconservatism among the football establishment.

Of course the odds of getting a smaller number of yards are higher than the odds of a larger number of yards, but would you rather have to be successful on two straight plays or would you rather try a slightly lower percentage play twice in a row with the knowledge that overall success only requires success 50% of the time?

I'd really like two distinct shots at success.
With that in mind, I'd make it my goal to get the first down on third down even if I knew I was going for it on fourth.

4. Brian Burke says:

Jeff-I think you misunderstand. No one is suggesting you actually don't try to convert on 3rd down, just that if the reads aren't there, the QB doesn't have to force the ball into coverage. There's a safety valve, but only if you go into 3rd down knowing you'll go for it on 4th down.

5. Jason says:

Jeff Clarke, I think the point is that if you know you are going for it on 4th down than you will take 7 yards on 3rd down but you still try to get the 10 yards. So you get the best of both worlds: 35% conversion rate on 3rd down followed by a 55% conversion rate on 4th down. Total that is 35% + 65%*55% = 70% which is better than your 57.5% chance of going for all 10 yards on 3rd and then 4th down.

6. Jeff Clarke says:

I think I might have been misunderstood. Obviously, I am not suggesting that anybody would just take a knee after they got 7 yards. There are plays that are designed to get 10-15 yards and there are plays that are designed to get 5-7 yards. The 5-7 yard plays have a lower probability of getting 10+ but they also have a lower prob of getting 0.

I think conventional wisdom says that you should probably call a 10+ play if you are planning on punting and a 5-7 play if you are planning on going. I think this CW is wrong.

I often see this occur where the coach calls a screen or a draw play on 3rd and it goes for 6 yards or so and the announcer says admirably that it was a smart call. I don't think it is a smart call.

I think the goal should be to get the entire 10 and if you need to accept a higher risk of an incompletion to get there, so be it.

If what you are talking about is just a safety valve where the primary and secondary receivers are both 10 yards away, I don't really have a problem with it. I would point out that isn't that much different than a normal third down. What I really have a problem with is when the call is a run or a screen and the realistic goal of the play is 4th and short and not a first down.

I think this has a lot of parallels to bunts in baseball. You are better off with a guy on first and no outs than a guy on second with one, yet managers routinely accept the trade.