Here we are, coming into the second season of the new world in which NFL extra points are a 33 yard FG attempt! As soon as week 1 of the 2015 season finished, there was near-pandemonium that the rule change was indeed achieving the desired result [link]. As the 2015 season played on, the week 1 trend continued and the increased difficulty of the extra point attempt drove an increase in two-point conversion attempts in a statistically significant manner [Figure 1].

*Statistics not shown, but regression of XPM (1pt attempts made) on XPA (1pt attempts) for data shown in Figure 1a yielded a t-stat of 249.7x and r2 of 99.99%

So, it worked? Hats off to the NFL! But I doubt the NFL believes the rule change affected the game strategies as much as they were expecting. Similarly, I don’t think any fan would say the experience of watching a game in 2015 was markedly different. Maybe you sat a moment longer prior to running to the fridge or bathroom to think about a kicker missing an extra point once or twice. But it’d be tough to say that teams are going for 2 enough to shift the in-game strategies of coaches and make the viewing experience more compelling. In fact, most NFL coaches still elected to take the 1 point option consistent with years past [Figure 2].

Looking at the numbers, 2015 saw 94 2pt attempts. That seems like a lot. However, if 2015 were like previous years, one would have expected ~59 2pt attempts. So that means the rule influenced 35 additional 2pt attempts after 1311 touchdowns. That’s an additional 2.7% of the time that coaches elected to go for 2. Not exactly a shift in tides.

Fortunately, when you dive into the data at the team level, things get a little more interesting. Looking back at Figure 2, there were a handful of teams that seemed to embrace the strategic option more frequently than in years past (significantly above their historical range). Of course, each attempt is unique and each decision is not made in a vacuum (would you be more willing to go for 2 if your kicker just missed an XP or a 33ish yard FG?). Without knowing the strategic criteria the teams actually deployed through the 2015 season, I would venture that 11 of the 15 teams above their historical range (left section in Figure 2) had a conscious strategy to seek opportunities where they could go for 2. In fact, those 5 leftmost teams alone made up 25 of the incremental 35 2pt attempts in 2015. That’s promising. But, all 5 should have gone for 2 more. Well, except for Cleveland… more on them in a minute.

A general problem with analyzing the NFL via statistics (let alone, just two point attempts) is that there just aren’t enough data points to draw meaningful conclusions. However, there are similar in-game situations to assess an offense’s effectiveness at converting a 2 point attempt which can provide additional data points for the analysis. If we add in a team’s success rate on 4th down and believe that it is a similar ‘do or die’ scenario offensively as a 2pt attempt, we significantly increase the total number of data points to analyze. Now, every team has at least 9 attempts to evaluate and the average number of plays per team is just shy of 18. Now, while all 4th down scenarios aren’t exactly the same as 2 point attempts (there is less at stake in many situations) the additional 4th down data points should at least make any conclusions about two point attempts more meaningful. So what does it say when we look at 2015 2pt and 4th down attempts collectively? That more teams should have gone for 2 more frequently. On the order of about 250 more attempts in 2015!

Figure 3 shows us the comparison of teams aggregate two point and 4th down conversion rates in 2015 (thick line). That is matched against their normalized expected value of going for one point (thin line = XPM%/2). Teams on the left part of the graph could have expected to generate more points through the season always going for 2 vs kicking an extra point. Similarly, teams on the right side should expect to generate more points by always kicking an extra point vs going for 2. Figure 4 then shows us incremental points a team could have generated had they deployed their dominant strategy after every TD in 2015. This brings us back to Cleveland — despite their seemingly conscious strategy to go for 2 more frequently in 2015, analysis shows they would have been better off on the season going for 1 more often (their collective 2pt and 4th down conversion rate was only 42.9% vs an 91.7% success rate kicking extra points).

I know what you’re thinking — not a lot left on the table for each team. The issue here isn’t necessarily that a team could have scored more through the course of the season. In many instances, an additional 5–10 points over the year could have been added to any team’s performance without affecting their season record. That said, an additional one or two points could have made a great difference for a number of teams (there were 21 overtime games in 2015). The point here is that many teams should have gone for 2 more often, because the situation and their offense allowed for it. With better data, teams could optimize for when it makes sense for them to go for 1 vs 2 in each situation and increase their scoring by a few orders of magnitude beyond what Figure 4 is showing. The results begin to become material and affect the in-game strategies of both teams, in turn, making more games more exciting (see footnote 1).

But teams know this and do what they do for good reasons…

True. Teams certainly have better data than this and they have people that can run meaningful analysis to give them the best edge possible. So what gives?

Like most statistical approaches to human behavior, there’s one thing that the numbers can obfuscate: incentives. It’s easy to say that the intent of each coach’s strategy is to win, and by extension, they will deploy a scheme that gives them the best chance to score the most points. However, each play following a touchdown is an independent event and each decision of whether to go for 1 or 2 is made on the margin. So to say, after each time a team scores they will only add 0, 1, or 2 points to their total. With no guarantees that they will score again the rest of the game, they more often than not choose the surest thing because coaches actually have negative incentive to go for 2 when they don’t have to.

Wait, what? Ok, consider yourself a coach who needs to decide what to do following a touchdown in this simple framework:

Well, this isn’t really a decision at all! Independent of probabilities or reality, there is a decision you can make which completely avoids the scenario where you look like an idiot (per the fans or the Owner). This is the proverbial no-brainer and coaches are smart people. The exception to this is where the reaction to missing a 2 point conversion is lessened because the scenario called for it (“there’s no reason not to go for 2 here”).

Winning is the greatest job security a coach can have. It is very difficult to win in the NFL. Not giving your boss examples of bad in-game outcomes to point to at the end (or middle) of the season is generally a good way to stay employed.

So where does this put us…

I think more teams will trend towards greater use of the 2pt option in 2016, but we still won’t come close to the theoretical ‘should’ level of ~20% of total attempts. I imagine that at the end of the 2016 regular season we’ll be just under 10% and I think that’s a level that fans and the NFL can be happy with. I estimate that some teams will start to use specific sets, plays, and personnel unique to their 2pt attempts, and their success will encourage others to follow suit in coming years. The NFL could continue to scoot the 1pt attempt back farther or create a 3pt attempt (both of which I hope never happen) in hopes to incentivize coaches to move away from the 1pt option. In the meantime, the same age-old factors will continue to trump the statistics in NFL coaches’ decision making processes: personal incentives and self-preservation.

Footnotes: