Re: Going for two each time Theory
 

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If the success rate is 50% on two point conversions, obviously your expected value is one point. So assuming 100% extra point attempt success rate and 50% 2 point success rate, the two options have equivalent EV(+1), but much different variance.

Of course 100% is obviously not accurate, and from my brief research i think the 2 point conversion success rate is probably more in the 40-45% range.

The key is recognizing the situations where you want higher or lower variance. Obviously if the game is tied with 1 second left, you'd want to reduce variance and kick it, and if you were down 2 with 1 second left, you'd want to increase your variance. Throughout the game obviously the decision would be less clear cut but would depend on the situation. All things equal though you'd want to choose the play with the higher EV, which in my opinion is kicking the extra point for most if not all teams.

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The reason that this is not correct is because by going for 2, you are not just risking the 1 point that you could have kicked. You are also risking other points that come into play when the other team adjusts their strategy to the result of your 2 point attempt.

Suppose a team has a 55% chance of making a 2 point conversion. If they run back the opening kickoff for a touchdown, should they go for 2? I think not.

45% of the time, they miss, and the other team can take the lead with a touchdown.

55% of the time, they are sucesful. Of this 50% of the time, the other team can tie with a touchdown (when they go for two because you did).

So 45% of the time, you would trail by a point if the other team scores.

27.5% of the time, you would be tied if the other team scores.

Only 27.5% of the time, you would lead by two points if the other team scores.

Add to this the fact that if you miss, the other team can tie with 2 field goals, and the argument against going for 2 becomes even stronger.

Unless you are playing a game in which scoring is done with basketball frequency, maximizing your expected points is not the same as maximizing your chance to win.

Re: Going for two each time Theory
 

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in Friday Night Lights, Dallas Carter went for 2 every time, all season.

seemed to work out fine for them

also, they barked like dogs before the state championship. not sure what affect that had.

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I'm sure that this is mostly a joke, but I'll just point out that in HS football, everything is different. Mostly because the extra point is often not a sure thing.

The team that I followed this year should never have kicked because they actually had a better chance at 2 than 1.

Re: Going for two each time Theory
 

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Unless you are playing a game in which scoring is done with basketball frequency, maximizing your expected points is not the same as maximizing your chance to win.

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I'm assuming most people here read David Sklansky's article a few months back about going for it on 4th down. The basis of his whole article was that you can calculate your EP(expected points) from any field position, your opponents EP from that same spot in case you fail, and your expected 4th down conversion success rate, and then compute your best play from that. He of course offered the caveat that it doesn't apply in certain situations where you'd want to minimize your variance, but in general it is correct. Now i'm not saying this method of analyzing football decisions is correct just because he says it is, but I do think that carries a lot of weight.

That said, I do think there is merit to your point about scoring frequency. Obviously if you scored a touchdown to tie and simultaneously the entire starting offense for the other team tore their ACLs, you'd definitely want to kick, as the chance of them scoring again has suddenly dropped to near 0. But I think that with moderately frequent scoring, maximizing EP is correct under normal circumstances not near the end of the game. But again, I think this will almost always mean kicking the extra point.

Re: Going for two each time Theory
 

There are times it may make sense to go for two even when it seems unnecessary. For example, I wrote this a while ago about being down by 14 late, scoring a TD, and going for 2 anyway:

"Assume you score two TDs, you make the 2-pt conversion 40% of the time, the PAT 100%, and the opponent doesn't score at all. Then the following are possible:

(1) You make your first two-point attempt. In this case you win because you kick the PAT on your second TD and win by 1.
(2) You miss your first and make your second. In this case you tie.
(3) You miss your first and second. You lose.

(2) is identical to kicking two PATs. (1) happens 40% of the time. (3) happens 36% of the time. So you come out ahead!

The problems is that coaches get blasted for unconventional gambles that don't work, but get only a bit of credit for gambles that do. You will be fired if you miss two 2-pt attempts in a playoff game and lose by 2.

...

The breakeven percentage for this is (3-sqrt(5))/2 which is around 38.1%. "

So even under conservative numbers, this works out well. In real life, it makes even more sense to follow this strategy, because 2-point conversions have more than a 40% chance and PATs have less than a 100% chance.

Re: Going for two each time Theory
 

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I'm assuming most people here read David Sklansky's article a few months back about going for it on 4th down. The basis of his whole article was that you can calculate your EP(expected points) from any field position, your opponents EP from that same spot in case you fail, and your expected 4th down conversion success rate, and then compute your best play from that. He of course offered the caveat that it doesn't apply in certain situations where you'd want to minimize your variance, but in general it is correct. Now i'm not saying this method of analyzing football decisions is correct just because he says it is, but I do think that carries a lot of weight.


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I didn't read this, but this idea is pure lunacy

Re: Going for two each time Theory
 

Now the 4th down deal teams should definitely do more often, especially against high scoring teams like Indy or USC who have such a high success rate anyways.

Re: Going for two each time Theory
 

Um, no. You can bet your ass Bill Belichick does this.

Re: Going for two each time Theory
 

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I'm assuming most people here read David Sklansky's article a few months back about going for it on 4th down. The basis of his whole article was that you can calculate your EP(expected points) from any field position, your opponents EP from that same spot in case you fail, and your expected 4th down conversion success rate, and then compute your best play from that. He of course offered the caveat that it doesn't apply in certain situations where you'd want to minimize your variance, but in general it is correct. Now i'm not saying this method of analyzing football decisions is correct just because he says it is, but I do think that carries a lot of weight.


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I didn't read this, but this idea is pure lunacy

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Okay, what the hell would you base it on? Your gut feeling?

Re: Going for two each time Theory
 

You guys are also forgetting that a PAT is not automatic. Your kicker will miss, occasionally, especially if his name is Jay Feeley. So say you make 50% of 2-pt conversions, but only make 95% of PATs, you already have an EV loss of PATs.

My problem with always going for 2 is defenses will spend a week preparing a goal-line stand against your specific offense and your success rate will drop below 50% to about 42%.

Re: Going for two each time Theory
 

I really don't think NFL kickers miss 1 of 20 PATs.