Using the two sources from the previous thread, here are the main statistics and probabilities that apply:

http://www.advancedfootballanalytics.com/i...d-epa-explained

http://blog.minitab.com/blog/the-statistic...ing-on-4th-down

Avg net points starting a drive at your own 12 yard line = 0.0 points

Avg net points starting a drive at your opponents 9 yard line = 4.5 points

Avg net points starting a drive at your opponents 34 yard line = 2.9 points

Avg net points starting on your opponents 45 yard line = 2.2 points

Avg net points for a drive starting at your own 42 = 1.3 points

% chance of getting 1st down on 4th and 1 non goal line situation = 70%

% chance of getting 1st down on 4th and 8 non goal line situation = 32%

Expected start of drive when D. Jones punts from around the opp 42 = 12 yd line

The Eagles Dilemma: Go for it 4th and 8 from the NYG 42 or punt it:

Expected points from getting the 1st down = 32% x 2.9 Exp pts from 34 = 0.93 pts

Expected points from getting stopped at the 42 = 68% x (1.3) = (0.88pts)

Net expected net points of going for it = +0.05 negligible

Net expected pts by NYG after punt to the 12 = 0.0

Total net expected points from going for it vs punting = +0.05 - 0.0 = +0.05. Very close to break even, thus why the 42 is right on the edge of the go for it/punt line on the chart.

The model says go for it 4th and 1 from anywhere. How can this be true?

The easiest case to disprove should be the 4th and 1 from your own 9.

If we go for it and get the first after an avg gain of 3 yds to have 1st down from the 12, then what is the average points we can expect if successful = 0.0

If we fail to get it and they get the ball at the 9, 1st and 10, what is the average points the other team should get = 4.5 exp pts.

When we apply the %'S to these outcomes you get:

70% x 0.0 = 0.0

30% x (4.5) = (1.35)

Net exp pts from going for it = (1.35)

Now compare this to punting:

If we punt from the 9 instead, on a average net of 36 yards, they get the ball on the 45 and based on the study, a drive starting there generates (2.2) expected points.

If we punt, the other team is expected to score 2.2 points. If we go for it, the other team is expected to get 1.35 points.

Going for it saves us 2.20-1.35 = 0.85 points.

Why does this seem so counterintuitive? I said previously that the chart was wrong and I intended to crunch some numbers and show how wrong it was! But I was wrrr. Why?

You can see that without factoring in the punt, going for it at the 9 is a loser proposition, netting 1.35 points for the other team. That matches the gut feel. Of course it's a loser. Who the hell goes for it 4th and 1 on the 9?

However, people don't think about the opportunity we give the opposition by punting to them. We are giving them field position where teams have historically scored 2.2 points. THAT is the part people over look. We save giving them an embarrassing 1.35 pts expectation by going for it, only to turn around and give them an acceptable 2.2 points as a result of following sound football coaching principles!

I find this fascinating.

Sure it needs to be tweaked to suit team's strength, momentum, time left etc. Sure you may be able to find other studies with slightly different success rates on 4th down and drive stats based on different time period and that may tweak it slightly. But the big picture is what the base chart shows is sound math and logic for a neutral situation. These are basic in that I make basic assumptions;

we will get 3 yards on the 4th and 1 if we make it.

If stopped at 4th and 8, we won't get any of the 8 yards on our failed attempt

Nobody will return our punt from our 9 for a TD.

These are conservative assumptions, and if I used more realistic assumptions, the decisions to go for it 4th and 1 or 8 would look better.

I was shocked in what I found in this analysis. I had intended to crow about how I was right and the chart was wrong.