2 Point conversion: Please chime in.....

[Stumpage]

I've always had questions about this aspect of the NFL since it was brought into the league years back...For example, there was a situation in tonight's New Orleans/Philly game when I thought that the Saints would be going for a 2-point conversion somewhat late in the third quarter to tie the game, but they opted for the single point.

While this was no doubt the right choice (Seeing that my NFL coaching experience remains stuck on Zero days), I was nevertheless left wondering why this decision was made.

Is there a specific chart or 2-point "bible" that teams follow? Aside from the obvious (Down 8 in the last minute) or some other no-brainer situations, when does the 2-pointer become an option? Is it ever considered a viable option much earlier in the game than the final quarter; Is it ever beneficial to start "chasing the points" early if you're trying to rally from a blowout, etc.

Anyway, I realize this is not the most important of threads in light of the "Pinnacle Crisis of '07", but any feedback at all would be appreciated. Could come in handy for the Patriots in my xbox league, or something all-important like that.....

[Ganchrow]

I posted this a while back in re two-point conversions:

In the NFL it is my understanding that since the advent of the two-point conversion in 1994 the league-wide probability of making a two-point conversion has been close to 50% (a bit lower, I believe) and the probability of making the extra point has been close to 100%. For the below analysis I use the numbers 50% and 100% respectively. Please let me know (citing a source) if the former figure is significantly off.

The NFL game history seems to be packed to the brim with situations where coaches foolishly forgo the two-point conversion. Here’s an interesting scenario I just thought of while anguishing in the dentist chair:

4th quarter, very little time on the clock (let’s say right around 2 ½ minutes). Team A has just scored a touchdown to bring it within 8 points of Team B. Ceteris paribus, should Team A take the extra point or should it try for the two-point conversion? Well clearly, based upon the content of the preceding paragraph, I’m sure you'll realize I’m going to argue for the latter. Here’s why.

With the small amount of time remaining on the clock, it is reasonable to assume that Team A will need to do two things to win the game: the first is to prevent Team B from scoring again; and the second is to score another touchdown. (Furthermore, it is unreasonable to expect Team A (except in the most pathological of cases) to score more than one further time in the quarter.) Now if Team A is fails to accomplish these two tasks, it will lose the game. This is apparent whether it converts 0, 1, or 2 points after this last touchdown. However, if Team A IS able to accomplish these two tasks, the situation becomes more interesting.

Let’s say that Team A goes for the extra point which, as per assumption, it makes with certainty. After it scores its next TD, it is then down by 1 point. If it chooses to kick the extra point there, the game goes to OT which, given our assumption of all else being equal, it wins with probability 50% (neglecting ties). If instead of kicking the extra point after the second TD it goes for two, Team A will still win the game with 50% probability (i.e., if it converts (probability 50%) it wins, if it fails to convert (probability 50%) it loses). Hence, if Team A takes the extra point after its first TD and manages to accomplish the two tasks outlined above (preventing Team B from scoring again in the quarter AND scoring another TD), it will win the game with 50% probability.

OK, now let’s say that Team A goes for the two-point conversion which, as per assumption, it makes with 50% probability. If it converts (50% probability, all conditioned on its accomplishing the “two tasks”) it wins after taking the extra point following TD# 2, if it fails to convert (50% probability) then, down by 8, it tries for the two-point conversion after TD# 2. If it makes that (50% probability) the game goes to OT. In OT it wins with 50% probability (once again neglecting ties). If it fails to make the two-point conversion after TD# 2 (50% probability) the game is lost.

So in the case of Team A initially going for the two-point conversion, conditioned on its accomplishing the “two tasks”. The probability of a victory = prob of making first TPC + prob of not making first TPC * prob of making second TPC * prob of winning in OT = 50% + 50%*50%*50% = 62.5%.

So to sum up: down by 8 after having just scored a TD near the end of the fourth quarter, the DEFAULT action for coaches should be to go for the 2 points. A coach should only go for the extra point if team specific factors would so dictate (say perhaps if Team A is sufficiently stronger than Team B such that it’s probability of winning in OT is greater that 62.5%, or if the Team A short-yardage game and Team B’s red-zone defense are such that Team A’s chance of converting a TPC would be less than 41.42%).


QED

[Dark Horse]

Another angle.
If the 2-pt conversion is made 50% of the time, why not use if aggressively, as intimidation factor, early in the game? Up 8-0 instead of 7-0. Early in the game a lead of 6-0 or 7-0 isn't that big of a deal anyway, because there is still so much time left. But going up 8-0 would be a statement.

[Seattle Slew]

Sean Payton made the right calls all night on the 2-pointers, even though the Saints bettors -6 might have wanted him to go for two. If Payton goes for two on either TDs in the third quarter and fails, the Eagles could have won the game on a late FG in that last drive instead of getting a tie if they drove down the field.

If the TD came mid to late fourth quarter, the play is to go for 2 because if you don't get it and are stuck up 5, odds are not enough time for two FG drives to beat you.

[Stumpage]

Great stuff guys, exactly the type of insight I was hoping for.....Wonder if we'll see any 2 point "do or dies" in the Playoffs this year or anytime soon (Like Boise State or Gruden a few years back) with the game on the line. I doubt it, and I guess it will always be the safe move to tie the game with the extra point and see what happens in OT, but it would be a memorable moment if any coach just decided to go for the 50% chance right then and there instead of waiting for the coin flip.....

[pags11]

biggest problem I see with the 2 point conversion is that coaches go for them too early and end up chasing the point late in the game (example: Nevada in their bowl game)...or they go for two when trailing 9, instead of kicking the XP to cut it to 8...then wait until the next TD to go for two...some coaches just don't think...

[cobra_king]

Never ever give up "free" points early in the game (before the 4th quarter) because they always come back to bite you in the butt later on. Anyone who's ever bet on a team that misses an extra point knows that usually this point comes back to haunt you in the end!

[Dark Horse]

Ganch mentioned that the conversion rate is about 50%. What if a team, through practice, could get that up to 60 or 70%?

The 2-pt conversion isn't even considered as an offensive weapon these days. How very strange! (That's similar to playing half-court basketball until a team, like the Suns, ignores the old wisdom and starts to run and gun.)

[Ganchrow]

Ganch mentioned that the conversion rate is about 50%. What if a team, through practice, could get that up to 60 or 70%?

It believe it's actually a bit less than 50%. Perhaps on the low 40s or so.

[Ganchrow]

This is the two-point conversion chart.

[Arilou]

I think a false assumption is being made here: The only goal of every coach is to maximize the % chance that his team wins the game. It isn't. It is a large goal, but it is not the only goal, and I'm not talking about covering. I'm talking about looking stupid, or being second guessed, or retaining the confidence of his players and his owner and GM. If I kick an extra point, only in obvious cases will I have to answer for it. If I go for 2, I have to explain myself.

So when I'm down 8, I kick the extra point and don't worry about the math. Technically you should go for 2 if it gives you >50% to win if you get 2 TDs, so if you think you're 40% to make it you should go for it. You then adjust for how good you think you are in OT; an underdog has more reason to break a tie. But who wants to lose their job this way, or read editorials about why they should?

In the bowls, it is very possible that going out with a bang and with style is a motivating factor. It is also possible that once one team, say Oregon St, goes for it and wins, that frees up teams like Boise to follow suit.

[BuddyBear]

biggest problem I see with the 2 point conversion is that coaches go for them too early and end up chasing the point late in the game (example: Nevada in their bowl game)...or they go for two when trailing 9, instead of kicking the XP to cut it to 8...then wait until the next TD to go for two...some coaches just don't think...

Great post Pags....Coaches like Hal Mumme ruin covers by going for 2 pt conversions early and in meaningless situations.

[rolemand]

What I can't figure out is why coaches don't instruct their defense to allow a TD late when they are down 1 with no timeouts and the offense will most likely kneel on the ball ending the game? Again a near 100% formality of getting the snap 3 times and ending the game.

[Arilou]

I know, rolemand. Many times the defense should let them in and the offense should run to the 1 and stop. But they're not trained to think that way, so it (almost) never happens.

[onlooker]

I thought a good time to go for two was when the Chargers made their last touchdown. If they failed, it would of been a 7 point game, if that made it, it would be a 9 point game. A two possession game. You miss the extra point or make it, its still a one possession game.

[Jay Edgar]

I thought a good time to go for two was when the Chargers made their last touchdown. If they failed, it would of been a 7 point game, if that made it, it would be a 9 point game. A two possession game. You miss the extra point or make it, its still a one possession game.

Interesting thought. One more thing to add to the list of Marty's sins tonight.

On the general question, I find it hard to believe that 2-pt conversions would be near 50% successful if run on a regular basis. (Teams don't convert 4th and 2 with that frequency, as far as I know.)

Most teams may have only a couple of plays in the playbook that they expect to have a high success rate (like a direct snap to the running back, for example), and you can't keep running those after every TD or the success rate would drop off the chart.

The other thought is that, even if the 2-pointer was a 55%+ proposition, the coach might not run it, feeling (even subconsciously) that any unorthodox approach that fails is a big threat to job security.

[Mudcat]

So much of the thinking around 2 point conversions is based on a What happens if we miss? mentality.

Personally, I would like to see teams take more of a, We're going to practice this and be aggressive about it and kick your ass approach.


(Although it should be mentioned that, as a bettor who always has an eye open for middles, I like the oddball numbers/differentials that are produced when there are more 2 points convert attempts in the mix.)

[TLD]

The approach the overwhelming number of coaches take, and what’s generally meant when they talk of “going off the card”, “playing it by the book,” “playing it straight,” “playing by the odds,” etc. I think can be summed up with two rules:

1. Prior to the 4th quarter, always go for 1.

2. In the 4th quarter, always play for a tie. That is, go for 2 if and only if it making it will tie the game, put you up by 3, down by 3, up by 7, or down by 7.

I certainly don’t believe that is the optimal strategy, and some very good reasons it is not are discussed in this very thread. But that’s what almost all coaches do. Arilou’s post is a good articulation of why they do, as long as we understand his point as an explanation rather than a justification.

[Justin7]

Ganchrow -

I dislike your 2-pt chart, because it doesn't factor in the time remaining, which is vital to this type of decision making.

This type of decision should reflect one thing: maximizing your chance of winning. The league-wide conversion rate is 45%. If both teams are likely to still score several times (when this decision is made in 2d and 3rd quarter), you are in effect giving up 1/10th of a point-expectation.

If you are down 2, trying to convert does one of two things: you tie the game, or the other team has a 2-point lead instead of 1. This encourages them to try to convert, putting the game on the "3". The comparison for being up/down any other multiple of 3/7 + 2 points will often give your opponent similar opportunities.

A key factor to consider for 2-pt conversions is: how many more scores are "expected" in this matchup? You can get an estimate by looking at the game total, and dividing by 5.6 points. So for a total of 56, you would expect 10 scores in the game. In a "good" game, where both teams can win, the scoring breakdown is 20% in the 1st and 3rd quarters, and 30% in the 2d and 4th. If both teams have at least 2 expected scores, it is almost always wrong to go for 2.

[BuddyBear]

regardless....Hal Mumee is still an idiot. Ganchrow please foward that 2 pt conversion chart to Hal Mumee

[Ganchrow]

Ganchrow -

I dislike your 2-pt chart, because it doesn't factor in the time remaining, which is vital to this type of decision making.

It's not my chart, it's the chart about which you often hear NFL color commentators commenting.

Quite obviously, there are countless factors not reflected in the simple chart, which in a proper game theory context would first need to be analyzed before deciding whether or not to go for 2.

In this post, for example, I've outlined an issue I found particularly interesting.

[pags11]

I still can't believe he went for that at the end of that game buddy...

[Arilou]

The "one possession game" argument is actually an argument FOR going for two. Why? Because it is all about information. Suppose I am down 9. If I kick an extra point now, then I am down 8. At this point, I don't know if I need one score (conversion is good on my next TD) or if I need two (it is not). I have no information. If I get it now, I can kick off normally knowing I only need one score. If I fail to get it now, I can onside kick or otherwise become very aggressive, knowing I need two scores, AND I can kick a FG to go down by 6 if I get into trouble. I make better decisions. The other team also makes better decisions, but they get far less from the deal. That's also the argument against going for it early: 8-0 tells the other team to go for 2, 6-0 tells them they don't have to.

The other thing that I noticed during the Pats game: There is a >51% success rate for 2-point conversions this year in the NFL, and that's before the one this weekend. Obviously, if it is >50% vs. <100% then the conversion is the play far more often than it is used.