How Much Does the New Touchback Rule Affect the NFL?
It's one of the most entertaining times of the year for the diehard football fan.
Even the casual spectator will note that free agency has largely slowed down and the available stars have signed with new teams, while the NFL Draft is still a ways off. Even further off is the news of OTA’s or training camp, so what on earth could be that exciting?
For junkies like myself, even the NFL Competition Committee’s rules revision period is an exciting time. One of the big developments to come out of the 2016 meetings is the fact that touchbacks will now be spotted at the 25-yard line in the National Football League.
It’s a simple change, for sure, but one that actually may have bigger ramifications than we think. When kickoffs were moved to the 35-yard line in 2011, ensuring more touchbacks, the average starting line-of-scrimmage plummeted, setting each drive further back from the start.
Just how much will tinkering with the touchback affect the NFL?
The first question we encounter has to be: why change the rule in the first place? Obviously, due to the increased research on concussions and severe contact injuries in the NFL, the league has become more aware of reducing high-injury potential plays. Kickoff returns have been perceived as one of those plays, especially back when the “wedge” of blockers was still legal and the kickoff was from the kicking team’s own 30-yard line.
Per one Football Outsiders article in 2013, the percent of concussions on kickoffs hasn’t gone down since these changes were made, though. The total volume of kickoffs – and therefore the volume of kickoff concussions – has. While reducing the total number of violent injuries, the kickoff is still a dangerous play, so the league has tried to incentivize returners to think twice about taking kicks out of the end zone with changes like these. The 25-yard touchback is yet another incentive like that. But has it worked in the past?
The table below shows the average kickoff return data, thanks to Pro Football Reference, from the periods of 1994 to 2010 (pre-kickoff spot change) and from 2011 to 2015 (post-change). Have these rule changes reduced the punch of the kickoff?
|Years||KO Spot||Return %||TD/Ret %||Yd/Ret|
The first thing to note from this table is that the rate of kick returns per kickoff dropped by nearly 50 percent as a result of these rule changes in 2011. Especially due to the stronger legs of kickers in the modern era, knocking the ball out of the back of the end zone for a touchback has been not nearly as difficult.
Many special teams units have decided that giving an opponent 20 free yards is not as bad as allowing them a chance for much more than that. They’re right to: since 2011, teams have scored 30.9 percent of the time on drives starting on their own 20 or further, and just 28.6 percent on drives starting inside that. The 2.3 percent difference in scoring probability doesn’t seem worth risking a home run kick return for a touchdown. This also has the added benefit, for the league, of reducing the number of chances players have to slam into each other.
You’ll notice, though, that the percent of touchdowns of kickoff returns has slightly increased from the earlier period to recent seasons, as has the average yardage per kickoff return. This may seem to indicate that the rules increased returns, but it’s rather that returners are only risking taking the ball out of the end zone when they have a clear field – and a good chance for a big play – ahead of them. For this reason, the number of returns is smaller and the value per return is higher.
Fixing A Hole
So, it’s clear that changing these rules does have a significant effect on league play. But exactly how impactful will incentivizing the touchback be?
For one thing, the average NFL drive from 2011 to 2015 has started around a team’s own 23.4-yard line, and just two teams had an average drive beginning further than the 25-yard line in this span of time: the Minnesota Vikings and New York Jets. In fact, only 23 out of the 514 players who have returned a kick between 2011 and 2015 have maintained an average of 25.0 or more yards per return on at least 50 returns (Cordarrelle Patterson of the Vikings, of course, leads the way).
This means that the other 30 teams will all get a couple of yards as a head start at a minimum, but will also get the security of knowing every kick they don’t return is a guaranteed 25 yards. It may not seem like a lot, but a five-yard average is significant when we consider scoring probability.
The table below shows the probability of a drive’s result from 2011 to 2015, comparing the chance of scoring on drives starting at the 20-yard line and those starting at the 25-yard line.
It makes sense that there isn’t a ton of difference in the chance of scoring a touchdown (just 0.40 percent), but there’s a 1.40 percent greater chance of scoring a field goal when your drives start five yards forward.
Not convinced that 1.80 percent greater scoring probability matters? There’s a significant difference in the value when we examine numberFire’s Net Expected Points (NEP) on each drive.
NEP is an analytic helps us take the numbers we get from the box score and shows how that player did versus expectation. By adding down-and-distance value to standard box score information, we can see just how much each play and each team as a whole influence the outcome of games. If a team passes for five yards on 3rd-and-2, it means more to the game than it does on 3rd-and-10, and those plays should be valued accordingly. For more info on NEP, check out our glossary.
When a drive starts at a team’s own 20-yard line, that play has an expected points value of roughly 0.40, meaning that at that position on the field on this down, we expect them to score that much on this drive. At the 25-yard line, that number is 0.66, or an increase of 0.26 points per drive starting from a touchback. This is a relatively big change in value (a 60.6 percent increase) that this rule will enact for those plays resulting in touchbacks.
Everything Has Changed
We aren’t fully certain of the tangible effect of this rule change yet, but we can guess at the ramifications based on previous data. With an average of 1,324 kickoffs per year going for touchbacks over the last five years, the new touchback would increase the initial expected points of each of those drives by 0.26. That means that -- if the touchback rates stay the same from the past four years -- the 2016 NFL will see an overall increase of 344.24 points, or a per-team average of 10.76. While that's not a ton by itself, that amount of points is significant over the course of a season.
Still, these calculations fail to take into account the fact that teams with good returners will have less of an advantage, and may see it as riskier to run the ball out. This would then reduce their average drive starting position, and likely their total points scored as well. We also don't know how this will affect the decision-making of kicking teams: do they continue to blast the ball through the end zone, or kick it high and short because the cost of a touchback is too high? What we do know is that kickoffs that result in a touchback just got 60.6 percent more valuable in terms of Net Expected Points, and that is not an insignificant amount for either units’ chances of scoring.
We can never fully rationalize out the shockwaves of a rule change, but -- honestly -- if it results in more scoring and fewer injuries, that will draw more fans. And all three of those things are certainly good thing for the future of the National Football League.