Going for two each time Theory

[Buckmulligan]

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Two reasons:
1. 6 points only ties 2 FGs, which is a common scoring increment. As you've established, the 2pt is roughly equal to the PAT, but loses big against 2 FGs.
2. Assume that each team scores 1 TD. If the first team goes for 2, it will lose a lot more than 50% of the time. 50% of the time it misses and loses. 50% of the time it makes. Then, the other team knows to go for 2, and ties the game half the time. Obviously, the real life situations aren't so formalistic, but the longer there is remaining in the game, the more this effect costs the converting team.


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It sounds like you have something worth-while to say but I'm not really following. Could you rearticulate?

[MyTurn2Raise]

awful, awful idea to go for two every time

These are not independent trials. The effect of going for two cannot be viewed in isolation. It directly changes the way the rest of the game is played.

missing does not cost just 1 point. There are hidden points lost later based on game situations. A team might have to later go for two to make up for a missed one earlier. It might become advantageous for an opponent to later go for two, and, if they make it, the missed opportunity cost 2 points then.

As the previous poster pointed out...making it might cause the opponent to go for two later where they can make it up.

EDIT: This is an example of what happens

[jstnrgrs]

In superbowl XXXVIII, both teams scored 4 touchdwons and one field goal, but the patriots won by 3 in regulation. Why? Because Carolina attempted a two point conversion to early. The failed attempt ultimatly cost them three points, which was the Pats margin of victory.

[MyTurn2Raise]

Another point: two point plays are tough to design. A team usually only has a handful of what they view as successful two point plays. Using them all the time would help defenses prepare for and be successful in stoping them in the future. The conversion rate would be sure to drop IMO.

It would also giveaway plays that teams use in goalline scoring situations.

[sam h]

Teams probably should go for two much more, just like they should go for it on 4th down more often. I think if you had a good offense, especially a good rushing attack that made running the ball a really creditable threat in these situations, and you invested a lot more time in drawing up and practicing conversion plays, you could easily get to a 60% conversion rate.

None of the arguments about the problems with falling a point behind make sense to me, since you are even more likely to pull a point ahead and put pressure on the other team to try a two-point conversion themselves.

[DougOzzzz]

[ QUOTE ]
In superbowl XXXVIII, both teams scored 4 touchdwons and one field goal, but the patriots won by 3 in regulation. Why? Because Carolina attempted a two point conversion to early. The failed attempt ultimatly cost them three points, which was the Pats margin of victory.

[/ QUOTE ]

No, the failed attempt cost them slightly less than 1 point.

[kenberman]

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.

[Triumph36]

No - it would just be increasing variance needlessly. Plus, the teams you'd score 2 on more often are probably teams you should be beating, and the teams you'd miss against are teams you need every point against.

Teams are not going to start going for 2 regularly.

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.

[jstnrgrs]

[ QUOTE ]
[ QUOTE ]
In superbowl XXXVIII, both teams scored 4 touchdwons and one field goal, but the patriots won by 3 in regulation. Why? Because Carolina attempted a two point conversion to early. The failed attempt ultimatly cost them three points, which was the Pats margin of victory.

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No, the failed attempt cost them slightly less than 1 point.

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IIRC, The score was 21-10 pats, car scored and failed a 2-point conversion 21-16 pats (net one point lost for car). Carolina scored again and again failed on a 2 pointer 22-21 car (net 2 points lost for car). The Pats scored, and made a sucesfull 2 pointer 29-22 pats (net 3 points lost for car).then carolina scored a touchdown, and the pats scored a field goal Final score 32-29 pats.

Both teams scored 4 touchdowns and a field gaol.

If carolina had not attempted the their first two pointer, none of the other 2 pointers would have been attempted. Assuming that the rest of the game went the same, had carolina not gone for two, the score would have been 31-31, and the game would have gone to overtime.

Perhapse you would rather look at it from an EV (I will call it EW for expected wins) perspective.

As I stated above, if Carolina had not gone for 2, the game would have been tied EW=0.5

Going for two:
1/8 of the time, the game will turn out as it did: 0.125*0

1/8 of the time, the pats would fail on their 2 pointer
this would have caused carolina to go for two after their final touchdown.
1/2 the time they would have made it, and the score at the end of regulation would be 30-30: 0.125*0.5*0.5
1/2 the time they would have failed, and the pats would win 30-28: 0.125*0.5*0

1/4 of the time, carolina would have been sucesfull on their second 2 pointer. This would have resulted in a 31-31 tie: 0.25*.05

1/2 the time, carolina would have been sucesfull on their first 2 point attempt. This would have caused the Pats to have to make a touchdown instead of a field goal as time expired. Lets assume the probability of them doing that is X: 0.5*X

EW=0.125*0+0.125*0.5*0.5+0.125*0.5*0+0.25*.05+0.5* X=0.15652+0.5*X

Since not going for 2 has an EW of 0.5, I then solve for X with EW=0.5

X=.17174

If you believe that the Pats chances of making a last second touchdown were less that 17.174%, then carolina was correct to go for 2. Otherwise they were not.