Will the rate of concussions increase if the NFL extends the season to 18 games?

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One of the key issues in the NFL labor negotiations is the expansion of the season from 16 games to 18 games. Owners want to increase revenues, but players are concerned about more injuries.

Of course the more games that are played, the more injuries occur. But I wanted see if the rate of injuries also increases as the season goes on.

And, I wanted to focus on the most debilitating types of injuries. The rate of ankle sprains or shoulder strains will not have the long-term impact on player health as major injuries. As a proxy for major injuries, I looked at concussions, which are clearly identified on NFL injury reports and are strongly correlated with long-term health issues.


The NFL has put a lot more focus on identifying and treating players with concussions this season versus previous seasons. Several high-profile players including Super Bowl MVP Aaron Rodgers missed time due to sustaining a concussion.

I know first-hand how dangerous concussions are: I suffered a massive one. Although I wasn’t playing football, I hit my head and blacked out, going into seizures and needing to be revived by medical staff. I was woozy for days. At that time, much less was known about the diagnosis and treatment of concussions, so my recovery consisted of lying on the couch. Like NFL players, the only thing I can do is hope I won’t suffer any long-term impacts.

Analysis Methodology

I examined NFL injury data from 2010 and compared it to 2000 to examine trends over the past decade.

I wanted to see if concussion injuries were up in general, and if more concussions are reported as the season goes on. I added up the number injuries reported including severity (from “Probable” to “Out”), position, and week.

Reported concussions are up 168% since 2000

Total concussions reported grew from a mere 36 in 2000 to 114 in 2010. However, more injuries were reported in general – from 3,449 in 2000 to 4,068 in 2010 (likely driven by stricter enforcement of reporting rules by the NFL), so normalizing for the overall increase in injuries yields a 168% increase.

But, were more concussions sustained or just more reported? To answer this, I examined concussions by quarterbacks who, I hypothesize, would be the most likely position for coaches and trainers to identify concussions back in 2000. Measuring the change in concussions for that position could be an indicator of an increase in concussions.

Quarterback concussions remained flat from 2000 to 2010

The number of weeks quarterback appeared on the official injury report with a concussion was 12 in 2010, up from 11 in 2000. When normalizing for the growth in injuries reported, there was actually a slight decrease in QB concussions sustained.

Does that mean that concussions are actually down in the NFL? It’s possible that the stricter rules around hitting quarterbacks has led to the flattening of quarterback concussions. So, to dig in further, I looked at concussions in other positions.

Concussions sustained by WRs and CBs have exploded

The real increase in concussions has come in the secondary. The top positions sustaining concussions in 2010 were at Wide Receiver, Cornerback, Linebacker, and Safety, all with large increases. None were among the top in 2000. The top positions reporting concussions in 2000, QB and Tight End, had very small increases.

It’s unknown whether there are more concussions today than last decade, or if the NFL is just getting better at detecting them. To attack this question another way, I looked for injuries that have become under-reported in the last decade to see if concussion-related injuries were buried there.

Hypothesis: Concussions were being diagnosed as neck/back injuries in 2000

Among the top injuries reported, only a few experienced decreases (normalized for overall growth). Knee, Shoulder, Back, and Neck injuries all declined. Of those, neck and back injuries could be the place where concussions were misdiagnosed in 2000.

The decrease in neck and back injuries is almost perfectly correlated to the increase in concussions over the past 10 years. Digging in further, for positions like WR and Safety, neck/back injuries are down (-14 for WR and -6 for S), but for some lineman they’re actually up (G +13, DE +7).

Now, this is merely a hypothesis, but it looks promising. It suggests concussions are not up over the past decade, they’re just better detected.

Concussions are a bigger problem as the season goes on

There’s one chart that the NFL owners do not want to see: the number of concussions reported as the season goes on.

Concussions steadily climb each week and start to hit double digits in week 12. In 5 of the next 6 weeks, double digit concussions are reported. Time is a great predictor of concussions, as the data, when linearly regressed, has an R-squared value of 75%.

If two weeks were appended to the end of the season as the owners are demanding, there’s one thing players should be certain of: more concussions. They should expect, as a collective group, 25 additional concussions as a result of that one decision. The players should either be negotiating to not expand the current schedule or to get better health coverage because they’re going to need it.

What should the NFL owners and players do?

I’m not a labor negotiator. But if I’m the players, wouldn’t sign up for 25 extra concussions, no matter how much extra money the owners offer. There is, in fact, middle ground.

Add bye weeks. It’s almost sad how simple the answer is. By adding bye weeks, the season is extended and more games can be shown on television, yet players do not have to play a single extra game. Adding 1, or even 2 additional bye weeks could net the owners similar revenue increases without the cost to the players’ health.

  • Tickets: Owners wouldn’t have to sacrifice any ticket money. Keeping 4 pre-season games would yield almost equal ticket money to swapping pre-season for regular-season games (season ticket holders are forced to buy pre-season tickets at full price)
  • TV: This is where the real money is. Adding games or adding bye weeks would do exactly the same thing – put more games on television. Whether the season is 16 or 18 games, fans are going to watch all of them. And with the explosion of fantasy football, viewers don’t care nearly as much about which game is on – they just want any game on.

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