Should you go for 2 down 8?
argmin.net
argmin.net
50% to 62.5% in the simplified calculation is a 25% improvement, not a 12.5% improvement. It's a 25% improvement on already low odds (after all, nobody is actually saying that it's 100% probability that your D will stop the next drive and then you will score another touchdown. It's just assuming that those things have to happen either way so the odds cancel out, and this is looking at win probability assuming that those things happen). Laura's calculations, for a similar scenario (4 possessions remaining), projects the overall probability of winning going from 11.2% -> 12.9%, which is a 15% improvement, roughly the same order of magnitude as the simplified example. I don't have the exact breakdown for a two-possession scenario, but in her slideshow she says this, which seems to be what the author is citing:
> If down by ...16 (before the 6 TD points), the strategy improves the win probability by <1%.
But I am convinced she is talking about absolute percentage points here (e.g. 10% to 10.9%), not a <1% change (e.g. 10% to 10.09%). Why? Because the slide has this before it:
> Rationale: if you are down by 15, you have to score two touchdowns while keeping your opponent from scoring
She is demonstrating that it's not a silver bullet given it's exceedingly unlikely you will win anyway.
In the linked blog post with the actual statistics in it, she argues that it only increases your chance from 11.2% to 12.9%, so it only really increases your chances by 1.7%. But that just seems to be dishonestly reframing the numbers so people think a 1.7% absolute increase is nothing. But that really is a 15% increase in win chance. It sounds like the data says the 2 points is even better than its proponents claim?
His only other argument is that failing the conversion psychs a team out, which I respect, but that's still just a bare assertion. I don't know why you'd get so mad at statistics for ignoring your feelings. People are complex and absent data otherwise, I would think it just as plausible that the added pressure and imminentness increases performance.
No, that's dishonest. Probabilities are already ratios between magnitudes (desirable vs. undesirable outcomes), so when comparing them you should be subtracting them, not dividing them. A relative increase in probability of 15% doesn't tell you anything if you don't already know the base probability. Also, why go for the 15%? You could also say that the loss probability is reduced by 2%. But I guess you don't get a nice juicy number that way.
One number never fully captures the reality. If I have a net worth of 1 penny and I earn a second penny, it is 100% true to say I've doubled my net worth. It also doesn't tell the full story.
If a coach can take an action that would move the win probability from 0.01% to 1%, it would be malpractice to not do so, and correct to say they've increased their win chances by a factor of 100. It's also correct to say they're probably going to lose.
I think you're using a restrictive and non-standard interpretation of percentages. They can be used to convey overall probability, but also a change in probability. Only allowing one usage is just a communication deficit.
Not in that particular case, because no one would believe in an increase of 100% (although it would still be preferable to say that it doubles your chances of winning). But if you're at a slot machine and you can put in an extra dollar for a 10% extra chance to win the jackpot, and in fact you chances increase from 0.001% to 0.0011%, would you think that's honest or scummy?
>They can be used to convey overall probability, but also a change in probability.
They can be. They shouldn't be used this way because it lends itself to miscommunication.
I think you are backwards from how other people regularly faced with this ambiguity have decided to communicate, given that e.g. finance created a separate term to talk about changes in percentages.
Using that terminology, the win chance has gone up by 160 basis points, which is an increase of 15% from its previous value.
[edit] fixed grammar mistake
Casinos in general are scummy, but I can't fault with the phrasing. What's the threshold at which the world is allowed to use percentages in the way they're meant to be used, without having to be accused of being dishonest?
> Under completely unrealistic assumptions, G42D8 improves the chances of winning by less 1%. If there is any uncertainty in these calculations at all, then you might even be putting yourself at a disadvantage!
This is implying (without out saying) that a tiny error in e.g. the probabilities of converting a 2 point conversion will make things a disadvantage. After all, what if there's only a 46% (instead of 48% from Ms. Albert's article) of making the 2-point conversion, that must surely lower your win chances by more than 1 percentage point, right?
The answer is "of course not" becuase that just lowers the win probability by a tiny absolute amount as well. In fact this can be seen in the flow-chart that TFA hates so much. The author is either being scummy and disingenuous, or has confused himself by mixing relative and absolute percentage changes.
It's important to distinguish the scummy behavior from the actual statistical practices, as data literacy helps people see through numerical slight of hand.
these are the assumptions they are attempting to debunk:
- All 2-point conversions are equally likely to succeed.
I have seen no evidence that all 2-point conversions *aren't* equally likely to succeed, and even if they were two bites at that apple gives you better odds than just one
- You will stop the other team from scoring.
regardless of whether you choose to go for it or kick the XP, you still have to stop your opponent on their subsequent drive. if they do so much as kick a FG it's game over already, so it doesn't matter.
- You will get a touchdown on the subsequent drive.
you have to score a TD or the debate doesn't matter so it's irrelevant to this argument
- The clock expires after that.
again we have to assume we are preventing the opponent from scoring any additional points because the debate makes no sense without that caveat
- There are even odds of winning in overtime.
getting to OT in this scenario is the fallback, while it's the best outcome of just kicking the XP twice in a row
(assuming you want to win in regulation which presumably you do because OT is inherent chaotic)
> getting to OT in this scenario is the fallback
I meant to say "likely fallback"
Pass plays are less likely to convert than run plays. The conversion rates aren't even equal between teams.
https://www.teamrankings.com/nfl/stat/two-point-conversion-p...
yes but in this instance we are considering the same team
Is this intended to be tongue-in-cheek? Reading such a statement (which logically implies that "if Todd Bowles had used his final timeout, the Bucs would have won") in a post about how other people's reasoning is insufficiently rigorous is off-putting.
Or Bowles mentally marked the game as over and then didn't notice the Lions messed up with the play clock.
> Now, had Bowles used his last timeout, maybe the Lions decide to punt instead of attempting a long field goal. But Bowles surmised a kick through the uprights would have ensued.
Basically, he would have had 36 seconds because of the clock mismanagement on the side of Detroit. Even with 0 timeouts, you can knock out 4-5 solid plays, which is a lot more than 0 solid plays. He goofed up.
https://apnews.com/article/lions-buccaneers-bowles-campbell-...
Claiming that the Bucs lost because of this error is way off, they almost certainly would have lost anyway.
I don't understand the point of the article. If G42D8 increases the chance of winning it's the way to go.
Doesn't matter how much the increase is as long it's an increase.
What the probability of losing if you don't G42D8?
Football Clock Management - https://johntreed.com/collections/football-coaching-books/pr...
The Contrarian Edge for Football Offense - https://johntreed.com/collections/football-coaching-books/pr...
Clock management is not just for the last minutes of the game, it is a fundamental part of the strategy for the entirety of play, starting before the game.
I enjoyed them from a not-really-even-a-fan perspective, somewhat like a Moneyball type of read.
If you're down 8, with limited time remaining, you should always go for 2 to tie the game, instead of still being down by 1. You'd still need a field goal to take the lead, and that would still be the case if you miss the 2pt conversion.
it is confusing because the conversation is taking place after you just scored
This is misreading the original source [1]. The <1% figure applies when you have not already gotten the first TD.
[1] https://punkrockor.com/2019/11/15/when-should-a-football-tea...
Down by 8 and facing a conversion opportunity means you were down by 14 and just scored a touchdown (6 points). It's more that 1 percentage point change (1.7%) not less (and as others have pointed out, it increases your win probability by about 15%), so there is still a misreading.
The possible choices you can make for 2 PATs are:
Kick, Kick
Kick, Attempt
Attempt, Attempt
Attempt, Kick
If you kick first, let's assume kicking is 100% successful, now your choices are:
Kick made => Attempt
Kick made => Kick again
These are both rational choices; attempting gives you a 50/50 shot to win, and kicking again sends you to OT with a 50/50 chance.
Now let's look at if you attempt first.
Attempt made => Kick
Attempt made => Attempt again (irrational!)
Attempt missed => Kick (irrational!)
Attempt missed => Attempt again
Some of these are irrational! If you made the conversion, just kick it to win by 1! This information gain helps you eliminate irrational choices, whereas if you kick first, no choices are eliminated for you.
And when they do, they will be able to capitalize on the information gained from your 2 point attempt.
In terms of expected value, 2 point conversion attempts are roughly par with extra points, though with so few scoring events in the game you would expect large variance.
So outside of scenarios where it is pure upside (1 point doesn't matter without many more scoring events) teams will opt for the lower variance outcome. This matches practice pretty well IME.
If Baltimore special teams doesn't let a punt return TD happen, Houston had one FG to their name... the entire game.
I don't expect a team will always score, absolutely not a team playing against one of the best defenses in football history. So, I respectfully disagree with your thesis. :)
I also suspect that the probability of converting for 2 goes down with each subsequent attempt. You can expect teams to have a few plays installed specifically for critical 2PC attempts, and you may not want to burn those plays for marginal gain early in the game.
if you fail, you still trail by 8
Or trail by 4, if you really botch it up.
- go for 2
- down 8
- convert
Or which sport they come from for that matter.
Some of these I could guess, but 'conversion' is a tricky one.