I lean slightly towards punting, but I don’t have strong feelings here – my numbers tell me that either punting or attempting a field goal could be the best play. Specifically, attempting a field goal would be the right call if you think your chances of making the kick are greater than 53 percent. (Based on my analysis of over 13,000 field goal attempts since 2001, I give the average kicker a 46 percent chance to make a kick from this distance in a outdoor stadium.)
Here's the full breakdown of my calculations:
Option  Chance of converting 
Chance of winning
Before play

After play  Change  

Punt  89%  89%    
Field goal try51 yard kick (est.)  46%  89%  89%    
Go for it4th and 20, opp. 34  10%  89%  88%  –1% 
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.
Field goal try  64% of the time 
Punt  32% of the time 
Go for it  5% of the time 
Dustin Colquitt punts for 25 yards to Cle9. Dustin Colquitt punts for 25 yards to Cle9.
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!