Implications of a 33-Yard XP

The NFL is experimenting with a longer XP this preseason. XPs have become so automatic (close to 99.5%) that there no longer much rationale for including them in the game. The Competition Committee's experiment is to move the line of scrimmage of each XP to the 15-yard line, making the distance of each kick 33-yards.

Over the past five seasons, attempts from that distance are successful 91.5% of the time. That should put a bit of excitement and drama into XPs, especially late in close games, which is what the NFL wants. But it might also have another effect on the game.

Currently, two-point conversions are successful at just about half that rate, somewhere north of 45%. The actual rate is somewhat nebulous, because of how fakes and aborted kick attempts into two-point attempts are counted.

It's likely the NFL chose the 15-yd line for a reason. The success rates for kicks from that distance are approximately twice the success rate for a 2-point attempt, making the entire extra point process "risk-neutral." In other words, going for two gives teams have half the chance at twice the points.


But it might not be so simple. Teams tend to pass too often on 2-pt conversions, and simply by running more often, the overall success rate could climb to near 50%. That would make the long-run expected value of a 2-point attempt higher than an XP kick attempt. In theory, the strategy options would flip roles. Two-point conversions would become the norm, and XPs would be reserved for late-game tactics when one point is all that's needed to win.

And even if the average 2-point success rate doesn't climb much above 45%, the rates for above average offenses are already above the break-even rate. The same is true for attempts versus below average defenses.

The net advantage of making 2-point attempts the default would be very small, only a fraction of a point per game, so either way, it's not going to make much difference. But that's not any different than how things are now. The net advantage of nearly always kicking the XP rather than usually going for two is tiny.

It's unlikely that the premium would be large enough to compel coaches to abandon convention, even for the best offenses. When two risky options are considered, it's usually the low variance option that's preferred. And in this case, that will always be the XP.

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9 Responses to “Implications of a 33-Yard XP”

  1. Anonymous says:

    Only if you are the underdogs, you want to use the high variance approach to increase your chances of winning.

  2. Brian Anderson says:

    I suspect the "true" conversion rate of PATs from the 15 yard line would turn out to be higher than 91.5%, if they ever moved them there permanently, for two reasons: 1) PATs will always be from the middle of the hash marks, and 2) there is less incentive for the defense to try to block a 1-point kick than a 3-point kick.

  3. Nate says:

    So there's now a different starting position for 2-point conversion and PAT kicks? I guess there's some rules in place to prevent 'fake' 2-point conversions.

  4. Ryan says:

    It doesn't make much sense to me to have them start on different yard lines -- now you'd never fake an extra point, because flat-out going for 2 is far easier from 2 yards out than from 15. What about faking a 2PC - is a dropkick still legal? Or do you have to run back to the 22 yard line to do that? Seems like overthinking something that doesn't need to be overthought.

    What about penalties? If a 15 yard penalty is assessed before a PAT, the resulting PAT is still makable from the 17. Now it turns into a 47-yarder. What if after the penalty you want to go for 2? Do you get to go for it from the 17? If not, seems like trying to force a penalty (offside, etc.) is much less risky for the defense than the offense.

    Just seems like an arbitrary rule that creates more complication than is needed, like the OT rules. Leave well enough alone, Goodell.

  5. Jesse says:

    I agree with Ryan. It doesn't make any sense to have the kick and the 2-point attempt from different spots.

    I think the better option would be to just move the line of scrimmage to the 1-yard line from the 2. This will not really change the situation for XP's, but will cause 2 point conversions to be completed at a rate above 50%, moving the balance of probability clearly in that direction.

  6. Kos says:

    "The net advantage of making 2-point attempts the default would be very small, only a fraction of a point per game, so either way, it's not going to make much difference."

    Is this actually true, though? Expected points are a great way to look at long-term success; however, in a clocked game with a finite number of possessions, and in a game where scoring isn't linear, can't we argue that gaining EP might be less important than "uniform" scoring?

    In other words, just because the change in EP is negligible does not mean the change in WP would be as well. This seems similar to bunting in baseball. We realize it's bad in a vacuum, but when it's tied in the bottom of the 9th, and you get a leadoff single/double, it is often beneficial for your WP to trade an out for 90 feet. You decrease your expected runs, but you only need one, so you're only concerned with the *frequency* of your scoring (as opposed to the volume of it). This seems like a study of diminishing marginal returns. If you're down by 6 and score a TD as time expires, it doesn't matter if your 2PC rate is 90%. Your EP would be 1.8 points (vs. 0.995), yet your WP would be 0.9 (vs. 0.9975), so you'd obviously just kick the extra point.

    My gut says that going/not going for 2, while potentially negligible EP-wise, could completely shift the way your opponent approaches the entire game. Maybe being up 8-7 in the 1Q doesn't change much, but being up 8-7 in the 3Q might change a lot. What if your opponent is less willing to kick a chip-shot FG on 4th and inches (since it would only put them up 10-8)? You've now "forced" them into the mathematically-correct decision of going for it. Even if the boost to their EP isn't much, the WP difference when they succeed is going to be quite large (especially if they convert their 2PC and go up 15-8), and that's a big issue when you'll only have 2-3 remaining possessions in the game.

    I think we at AFA all agree that math is a wonderful tool to use for analyzing football. However, in a league where most coaches act irrationally and coach sub-optimally from a tactical POV, I'm not sure it's possible to accurately analyze the psychological impact this scoring change would make. If we're all willing to accept the idea that you'd sometimes rather be down 6 than be down 3, why are we so sure that being up 1 is always better than being tied? Is it not possible that, when down 7-0 and scoring a TD, matching your opponent's score could be smarter than being up 8-7? In a league where coaches LOVE to play for ties (which is obviously a mistake), why would you take away their opportunity to play for that tie? To put it another way: if your opponent is already making tons of mistakes and coaching with zero regard for math, why would you do anything that could alter their approach? Coaches will only start questioning themselves and actually using their brains when their backs are up against the wall (see: 2013 Ron Rivera), so don't make them feel like their back is up against the wall. Let them continue to be complacent, and keep reaping the benefits.

  7. Kos says:

    One thing to add to the above: this is why I vehemently disagree with the general belief that, if you're down 14 late in the 4Q and score a TD, you should go for 2. While the math backs it up, we have no data to confirm how coaches coach when up 7 vs. up 6. If your opponent is happy to take three dives and punt when down 7, are we sure they do that with the same frequency when only up 6? Does that possible dip in their 3-dives-and-punt frequency actually end up negating (or worse, outweighing) the EP boost you get from going for 2...and is this even measurable?

    (For the record, I obviously 100% agree with going for 2 in scenarios where the game ends if your opponent possesses the ball again. When you are the only one who controls the ball, the psychological impact on the opposing coach is irrelevant, so going for 2 becomes inarguably correct.)

  8. Anonymous says:

    > ... In other words, just because the change in EP is negligible does not
    > mean the change in WP would be as well. ...

    All the evidence that I'm aware of indicates that the impact of in-game psychology in the NFL is pretty small. As Romer said in his podcast, the players are professionals.

    However, the nature of scoring is such that whenever that second point is worth a lot more than the first, teams really ought to be going for it. The most familiar example is teams that are down by 2 in the second half, but, really, it should be considered by teams that are down by 5 or up by 1 before the PAT as well.

  9. Hugh Nightingale says:

    I must admit no paying any attention to the trial of XP from the Def 15 during Wk1 and Wk2 of pre-season for reasons stated above and upsetting the delicate balance marginally in favour of one over two in terms of EP over the course of the game.

    It does not bother me that the XP is almost automatic as its primary function is to give the TD package an edge over two FG, period.

    The option to go for two should generally be in game situations where relevant to the score; the 2MW game has now proved several times the correct option is to take the single point until roughly the last six minutes or so, but then I have been able to slew the rules to reinforce this!

    Suppose PAT were taken from the 15...then would there be a need to then move the two-point option to the Def 3 to keep the balance between the two over the course of the game? Too complicated and what about the surprise element touched on above?!

    What you could do, if you wanted to make the PAT marginally less likely, is tinker with wider hash lines for use in Q1, Q2 and Q3, or even up to the Last Five Minutes. Subject to these marking the extreme, the PAT would no longer be taken from the centre of the field but in line with where the ball crossed the GL (rushing) or caught in the EZ (passing). If the officials are in doubt, the widest alternative is the mark.

    By essentially copying the NFL model, the 5+2 system used in rugby union actually produces a better statistical range of points: here it depends where the ball is touched down not where it crosses the try line. In theory at least the two points for a conversion in front of the posts is even more automatic than the three-player exchange needed in Football, but is still worth less than the three points for a penalty goal. Yet in many cases the conversion attempt can be more difficult than a penalty. Again, it is a delicate balancing act to ensure a converted try is worth more than two penalty goals.

    Association Football is no different although scoring is more straightforward: if the GA can be raised to around four then the net affect of a penalty goal is diminished.

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