Week 3, Vikings at Panthers
4th-and-4, 8:12 remaining in 2nd quarter, Down by 8
The Vikings punted on a 4th-and-4 on their 9. The NYT 4th Down bot mentally high-fives that call, although going for it would have been fine, too.
If you disagree

I lean slightly towards punting, but I don’t have strong feelings here – my numbers tell me that either punting or going for it could be the best play. Specifically, going for it would be the right call if you think the Vikings’ chances of converting on fourth down are greater than 50 percent. (Based on my analysis, I’d give the Vikings a 48 percent chance to get a first down here.)

Here's the full breakdown of my calculations:

Option Chance of converting
Chance of winning
Before play
After play Change
Punt 10% 10% -
Go for it4th and 4, own 9 48% 10% 10% -
Field goal tryA really, really long kick <1% 10% 6% –4%
My decision in context

Along with some circuitry to come up with a win probability for every game situation, all you need to figure out what you should do next is an estimate of how likely you are to make a field goal or convert a first down.

My estimates for these are based on the results of thousands of similar plays, but you may think you're smarter than I am. This chart shows you how changing those estimates would change my recommendation.

What to do on 4th-and-4 on own 9
Down by 8 with 8:12 remaining in the 2nd quarter
What coaches usually do
Punt 98% of the time
Go for it 2% of the time
Field goal try -
Based on about 286 fourth downs in similar situations since 2001.
What happened

Jeff Locke punts for 44 yards to Car47. Jeff Locke punts for 44 yards to Car47.

Where did these numbers come from?

To estimate a team’s chances of winning, I use a mathematical model that accounts for a whole lot of variables — including the difference in score, the time remaining in the game, and the number of timeouts each team has left. On top of that, I have models for the likelihood that a team makes a field goal and the likelihood that it will convert a first down.

By combining all of this information, I can come up with the best decision a team can make, according to math.

If you want even more details about the numbers behind my decisions, my full model is available on GitHub. Help make me better!