The “math” of going for 2 makes no sense

[JMF2006]

I like 2 point conversions.

 

I like that the Bills practiced one on that last TD.

 

I just hope they throw that play in the trash and never use it again.

 

 

[BuffaloBill]

On 10/31/2021 at 6:39 PM, Special K said:

Analytics have ruined baseball, poker, and now they are slowly creeping their way into football......stick to accounting, nerds!!!!!

 

 

But nerds would rule the world if the rest of you would quit spawning….

[dave mcbride]

On 10/31/2021 at 7:54 PM, Miyagi-Do Karate said:

If they make it. If they miss it, then they put a lot more pressure on themselves to even have a chance to tie. 

2 pt conversions succeed at over a 50 percent rate. If you try it twice, odds are you'll make one. If you make it the first time, you can end the game with an XP and avoid OT, which is a 50/50 proposition.

Edited November 2, 2021 by dave mcbride

[Miyagi-Do Karate]

58 minutes ago, dave mcbride said:

2 pt conversions succeed at over a 50 percent rate. If you try it twice, odds are you'll make one. If you make it the first time, you can end the game with an XP and avoid OT, which is a 50/50 proposition.

Not to beat a dead horse, but how can anyone say those stats are statistically significant? No team goes for it enough to generate enough stats that would tell them their true 2-point success rate. And you cannot, IMO, extrapolate from a league average over the last x years. I mean, the stats currently show Houston has a 100% success rate on 2-point conversions. That is unlikely to be the true probability for that team. 

[Shaw66]

On 10/31/2021 at 7:20 PM, Rew said:

The math is pretty easy of why to go for 2 near the end of game.  In overtime you tie around 7% of the time.  Meaning you win around 46.5% of the time in overtime.  You miss the XP around 7% of the time.  That gives you an expected win% of around 42% it you go for the xp.  If you think you have a good play schemed up that you can make the 2 pt at better than 42% chance you should go for it.  

Yours is the only analysis that comes close to the reason you go for two.   Most everyone else thinks the answer to the question is found by thinking about probability of getting one point or two points, and maybe about whether the other team will score again.   The actual analytics calculation is much more complicated.   The question is whether, down eight, our chances of winning the game are better if we go for one or go for two.   Chances of winning the game.   

 

That calculation depends on the probability of converting this two point conversion, chances of converting the next one, chances of converting each PAT, chances of scoring again, chances of the other team scoring again, chances of the other team making the PAT, chances of going into overtime, chances of winning in overtime.   All of those probabilities are team-specific - that is, if I'm playing Jacksonville, a lot of those probabilities are different than if I'm playing Arizona.  

 

The probabilities are recalculated every week, depending on how your team is doing and who your opponent is.   

 

During the Auburn-Ole MIss game they talked about it a lot, because Kiffen goes for it on 4th down a lot and goes for two often, and they said his decisions to do so are based on different analysis each week.  

 

The classic example was when Belichick went for it on 4th and 2 from his own 30 with a minute left, up three against the Colts.  He didn't make it, Peyton drove the 30 yards for a TD and won the game.   Belichick was absolutely ripped in the press for not punting.   A few days later, the math came out, and he was right.  His chances of winning the game were better going for it.   He had something like a 70% of making the first down, and if he made it, he had a 99% chance of winning the game.    So going for it gave him 70% chance of winning.   If he punted, he could give up a return for a TD or for big yardage, or Peyton could drive in the time remaining.   Punting meant the chances of the game being tied and going to overtime were pretty high, in part because it was Peyton.  If it went to overtime, your chance of winning was 50-50, more or less.  Or you could lose in regulation.  When you calculate all the probabilities, it was clear that punting gave Belichick less than a 70% chance of winning, so going for it was the right call.  

 

All I know is that when the Dolphins got the two points, it was a six-point game and I was very uncomfortable.  That alone made it the right decision.  Your opponent is going to play more scared with a six-point lead than with a seven-point lead.   

[Special K]

1 hour ago, BuffaloBill said:

 

 

But nerds would rule the world if the rest of you would quit spawning….

 

Being smart is great, but sometimes I think analytics makes sports too robotic and takes the feel and gut instinct of the coaches and players out of play.

 

Also, sometimes if you try to be too smart, you end up outsmarting yourself!!

[benderbender]

I would go for 2 on every TD drive over 10 plays. The defense couldn’t stop you AND they’re tired. Strike while the iron is hot.

[Watkins101]

I don’t know the exact numbers, but it seems the past couple years, this team has been horrible against 2 point conversions, I’d guess giving up at least 60%. If we were to assume 60%, the expected value of a 2 point attempt would be 1.2, which would indicate the better thing to do would be to go for 2 all the time against the Bills. Likely, with more attempts, the rate would go down however.

[Shaw66]

3 minutes ago, benderbender said:

I would go for 2 on every TD drive over 10 plays. The defense couldn’t stop you AND they’re tired. Strike while the iron is hot.

This too is a very good point, and even this point is more complicated than that.   You're saying the probability of converting the two point try is better after a long drive.   Maybe it is.  But it also may be better after a pick six, or after a kickoff return for a TD.   The probabilities no doubt vary, and I suspect that all of those probabilities go into the calculations, too.  

Edited November 2, 2021 by Shaw66

[unbillievable]

Since they moved back the XP, it actually makes more sense to go for 2 every time, going by league Average.

I think the math is something like If you went for it 300 times, you would get a +1 differential vs doing just XP.

 

Also, it affords the team real game time practice in goal-line situations.

 

However, situationaly, each team should analyze their kicker (Bills have a good one), the opposing defense, and their offense' red zone efficiency (Bills have a bad avg). So Buffalo shouldn't doing it that often. Additionally, they should stop kicking XP when the game gets out of hand.

 

It's similar to what happened in the NBA with 3point shooters.

[billsfan89]

The Fins “math” made sense because they were underdogs on the road. Generally speaking chasing points is bad unless you need it to cut the lead back down to one possession or you are down 5 and need to cut it to a field goal or some other specific reason.

 

Overall I would like to see the NFL get rid of the kicking extra point and replace it with a 1 to 3 point conversion system. A standard two point conversion becomes the extra point. Moving the ball to the 12 makes it a two point conversion and moving the ball to the 30 makes it a three point conversion.

[unbillievable]

I also feel that field goal points should increase every 10 yards.

 

under 20 = 1 point

30yds = 2points

40yds = 3points

50yds = 4 points

60yds = 5 points

 

This would come with the option for teams to move the line of scrimmage back, so they can increase their point try.

 

Although, this might screw up TDs, since some teams have good enough kickers that hitting 50yards would be easier. So maybe eliminate 30yd and 50yd distances.

Edited November 2, 2021 by unbillievable

[djp14150]

On 10/31/2021 at 5:42 PM, Miyagi-Do Karate said:

I absolutely despise teams going for 2

Based on the so-called “math.” The “math” strikes me as flawed many times. 
 

For example, why in the world did the Dolphins go for 2 when they cut the lead to 17-9 today? If they miss that, then they have dug themselves into an unneeded hole just to tie. If they make it, so what? Their “math” assumes the Bills wouldn’t score again, and the bills promptly kicked a FG, making it a 9-point game. So they basically took an unnecessary risk. 
 

I guess my biggest gripes about it

are:

 

1) coaches often go for 2 without taking into account the variables of the other team scoring again. That’s why I don’t think you should go for 2 until you absolutely have to— the very end of the game.

 

2) teams overvalue their success rates for going for 2. No team goes for it enough to have enough data to make a data-driven decision. And you can’t extrapolate (well) based on league averages because teams vary greatly in red zone/inside 5 success rates. 

 

 

I am a professional data scientist so I can explain why they decide this 

 

Recall probability

 

rolling a die. The odds of getting any one number is 1 out of 6 or mathematically 1/6 as a fraction

the odds of not getting a specific number is 5 out of 6 or 5/6

 

1/6 x 6 sides of a die =1

 

looking at making a PAT…say it’s x

failure is then 1-x which we can call y

 

similarly for going for 2 has a probability of T

probability of failure is 1-T or we will call this U

 

a team is down by 2 touch downs. If the score 2 touchdowns and two PATs would be= x*x. 1- that means they fail to tie.

 

if the opt to go for two and succeed they can actually win the game. If the miss both they lose.even if they miss one and made other they are still tied.

 

the probability of them failing both 2 pt tries is

 

(1-t)*(1-t)

 

if they do both PATs they lose if they don’t make both (1-x)*(1-x)

 

using real numbers

 

say odds of making a PAT is 0.9 so failing is 0.1

 

making both is 0.81=0.9*0.9

 

say your odds of making a 2 is 0.7 so failure is 0.3

 

you need to fail both so it’s 1- both failed. So 1-0.3*0.3=.91

 

0.91>0.81 and you have the added bonus of winning.

 

there are some probability combinations that the better option is kicking both.  If you have a very good kicker and conditions are not a factor say they are 0.96 in terms of making

 

this gives 0.9216 which is higher than the 0.91 from the 2 pt tries from above.

 

 

 

 

 

 

[WhoTom]

On 10/31/2021 at 5:39 PM, Special K said:

Analytics have ruined baseball, poker, and now they are slowly creeping their way into football......stick to accounting, nerds!!!!!

 

Yeah, who needs informed decision-making when you can just go with your gut instinct?

 

 

[djp14150]

On 10/31/2021 at 6:39 PM, Special K said:

Analytics have ruined baseball, poker, and now they are slowly creeping their way into football......stick to accounting, nerds!!!!!

 

analytics is used in order to help win a bet in cards or other gambling games.  It also sets the lines on sports betting.

 

baseball and golf are close to pure data collection strategies on patterns and suv es and failures.

 

football like hockey are much harder in individual analytics because it involves teams working together. Like against a D on a YD you might not be sure on cover responsibility like was a safety supposed to cover a deep corner or was the corner supposed to plan man vs a zone.

 

 

[YattaOkasan]

On 10/31/2021 at 5:55 PM, Cheektowaga Chad said:

The math going for 2 when scoring a td down 14 to cut the lead to 6 is all about winning the game in regulation. 

 

The math on getting a successful 2 pt conversion is nearly 50/50. So if you for 2 on the first td, and its successful your chances of winning in regulation improve dramatically. If you miss you go for 2 again and statistically you have a better chance of making it after missing 1 already

I agree with you from the onset.  Don't agree with your last line.  If you go for it again you odds dont change.  your language implies that the odds change on the second attempt because the first attempt failed; thats not true, Its still 50/50.  But again agree with you notion that at the onset if you are committed to trying twice you have 75% chance of getting at least one.  

[unbillievable]

1 minute ago, WhoTom said:

 

Yeah, who needs informed decision-making when you can just go with your gut instinct?

 

 

 

For the traditional crowd who wants decisions made on gut instinct, we'll always have referees for that!

[Cheektowaga Chad]

26 minutes ago, YattaOkasan said:

I agree with you from the onset.  Don't agree with your last line.  If you go for it again you odds dont change.  your language implies that the odds change on the second attempt because the first attempt failed; thats not true, Its still 50/50.  But again agree with you notion that at the onset if you are committed to trying twice you have 75% chance of getting at least one.  

Your last line is what my last line is

 

Yes each individual event is a 50/50, but as you add events probabilities/odds/chances do change

 

The odds of flipping a coin 5 times and getting heads each time is something like 3%. 

 

I was trying to simplify a mathematical conversation on a football message board 

[YattaOkasan]

1 minute ago, Cheektowaga Chad said:

Your last line is what my last line is

 

Yes each individual event is a 50/50, but as you add events probabilities/odds/chances do change

 

The odds of flipping a coin 5 times and getting heads each time is something like 3%. 

 

I was trying to simplify a mathematical conversation on a football message board 

Fair I read it as the last attempt is not 50/50 cause the first attempt.  I read your other posts and did come away with it being loose language not misunderstanding.  

[JohnNord]

It a gamble like a lot of decisions but there are times when it makes a ton of sense.  If Houston did go for 2 both times, they likely don’t beat the Bills in the 2019 playoffs to offset a 16 point loss.