Week 1, Chiefs at Texans
4th-and-9, 3:21 remaining in 3rd quarter, Up by 18
The Chiefs punted on a 4th-and-9 on their 36. The NYT 4th Down bot thinks that’s a great idea, 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 Chiefs’ chances of converting on fourth down are greater than 62 percent. (Based on my analysis, I’d give the Chiefs a 31 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 96% 96% -
Go for it4th and 9, own 36 31% 96% 96% -
Field goal tryA really, really long kick <1% 96% 94% –2%
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-9 on own 36
Up by 18 with 3:21 remaining in the 3rd quarter
What coaches usually do
Punt >99% of the time
Go for it -
Field goal try -
Based on about 1,805 fourth downs in similar situations since 2001.
What happened

Dustin Colquitt punts for 56 yards to Hou8.

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!