Should NE Have Gone For It on 4th and 1?

Ahead by 3 with 2 minutes left to play, NE faced a 4th and 1 from their own 49. In a move reminiscent of the infamous 4th and 2 call against the Colts last season, Bill Belichick went for the conversion. RB Ben Jarvis Green-Ellis was dropped two yards shy of the line of scrimmage, turning the ball over on downs to a rallying Chargers team. Was it a good call?

From midfield, punts tend to net 35 yards, giving the Chargers possession at their 16. With just under 2 minutes to go and all 3 timeouts, SD would have a 0.15 WP.

A successful conversion for NE wouldn't seal the win. Because SD still had 3 timeouts, they'd need one more first down. Since it's uncommon that the trailing team would have all 3 timeouts, to estimate NE's win probability properly, we'll dig one level deeper. Teams up by 3 near midfield with 2 minutes to play convert 1st downs 45% of the time. So a successful 4th down conversion seals the game 45% of the time, and it leaves SD with the ball near their own 15 with no timeouts 55% of the time, worth 0.12 WP. This essentially gives SD a 24% chance to get the FG, and then a 50/50 shot in OT. A successful conversion would be worth (to San Diego):

(0.45 * 0) + (0.55 * 0.12) = 0.066 WP

A failed 4th down conversion attempt gives SD the ball at (or near) the NE 49 with about 1:50 and change. That would be worth 0.32 WP for SD.

4th and 1s are converted 74% of the time in that region of the field. That puts the overall WP (for SD) for going for it at:

(0.74 * 0.066) + (0.26 * 0.32) = 0.13 WP

In this case, the baseline numbers say the percentage play would be to go for it, but not by much. The reason it's not a slam-dunk call is because SD had their timeouts. Last year, against the Colts, a conversion would have sealed the win because Indianapolis only had one timeout.

This situation is a great lesson in why going for it is an undervalued strategy. Even if the attempt fails, you still have a very good chance of winning the game. SD did manage to drive into FG range, but missed a 50-yarder.

13 Responses to “Should NE Have Gone For It on 4th and 1?”

1. Jonathan says:

Breakeven % is 67%. This seems like a situation where fourth-and-four feet would be a good idea to punt.

2. Brian Burke says:

That's really the best way to look at it--calculate the break-even and let the coach make the judgment.

3. Anonymous says:

What about the Chargers decision to go for the FG on 4th and 2 or 4th and 7 after the false start?

4. StL Reflections says:

Whats amazing is that the Chargers lost because of another comedy of errors. Not special teams, this time, but turnovers, which are mostly random events, so that they still won't suffer horribly in the rankings. What a strange team.

5. Anonymous says:

As a Texans fan I couldn't help but smile when Kris Brown missed that field goal. :)

6. Ian Simcox says:

Can I claim an assist on this one? I made a similar point about the timeouts in the live graphs.

I did do some very quick blurry eyed maths just to see what effect the timeouts have and I got to the same conclusion - it's almost a dead heat as to whether to go for it or not.

The other thing to consider when determining whether it was the right call is that going for it is trying to win using your offense, the punt is trying to win through your defense. The Chargers are #1 ranked on both sides of the ball, the Patriots have (now) the #15 offense and #24 defense (on yards/play). That would suggest that you should rather trust your offense to get you the win - making the go for it call the right one.

7. Kulko says:

In general I would agree with your sentiment, but having watched the game I felt that our chance of success was much smaller than 67%.

And while the Pats offense is typically their better unit, I would have trusted that night rather on the defense who held up okish, apart from that stupid prevent drive in the fourth Q.

8. Kulko says:

PS: Thanks for putting theses data up always so fast, especially as you take your time to make it a full article before posting it.

9. Anonymous says:

I see the reverse of this whole Belichick 4th down saga. Last year in Indy, I think that was the right call due to the fact that NE's defense had once again helped blow a lead, not to mention the fact that they were playing Payton Manning and Co. If we had given the ball to the Indy offense ANY spot on that field that night with two minutes to go and even only 1 timeout, I believe that Indy would have scored. And even though they failed to convert, they still almost stopped Indy in a series of plays that reminded me of the Goalline stand in 2003. Yesterday, I think was a bad decision. The Chargers had all 3 timeouts AND the Chargers were playing horribly on offense. Their defense was playing great and our offense was so so. So, why not punt it to them and force them to go the whole field without a mistake (a tall order the way the C offense played yesterday)?

10. James says:

Because we know from beyond just that one game that the Chargers offense is good, the Pats defense (particularly passing defense) is bad, and that the Chargers would likely be able to move the ball at least into field goal range if not score a touchdown.

11. Jeff Clarke says:

If they made the first down and then didn't make another one, San Diego would have gotten the ball back on their own 15 with about 1:00 left and no timeouts.

They'd need to go about 60 yards in 60 seconds to get the tying field goal. 24% seems way to high under those circumstances. Its essentially the same probability as with all their timeouts and 2 full minutes.

Since they need to get a yard a second and even just getting to the line of scrimmage to spike it seems to take at least 7 or 8 seconds, I just don't see this. Their probability would have to be significantly lower with 60 seconds and no timeouts than it is with the full 2 minutes and all the timeouts.

I'm thinking that you might have overlooked the fact that SD would have to call timeout immediately after the 4th down conversion and would have only 2 left to call after first and second downs. NE would be able to drain the full play clock after 3rd. Was it possible you overlooked that and were working off of SD being able to call timeout after all three runs?

12. Brian Burke says:

Jeff-You're correct. In that case it would be close to 0.18 WP for that situation. Making the go-for-it case slightly stronger.

13. Ian Simcox says:

Just watched the highlights on NFL.com. On the opening drive o the second half the Patriots had a 4th and 1 that they went for and made - with an off-tackle rush to the left. The play that got stuffed - off tackle rush to the left.

It doesn't take advanced stats to know you don't run the exact same play against the #1 defense. Right call to go for it - wrong call on the play choice though.