Thursday, February 12, 2015

Are NFL Teams Faking Injuries? - 2013 Follow-up

After I finished looking into NFL injuries during the 2014 regular season, we saw a couple distinct insights:

- Defenses appear to suffer more in-game injuries than offenses
- Injury stoppages occur more as the game goes on, with the fourth quarter having the greatest frequency of injury stoppage
- There is a positive correlation between offenses which run more plays and opposing defenses suffering injuries - but no such correlation between play frequency and injury in any other game situation

To me, this at least suggests the possibility that defensive players fake injuries against high-tempo offenses. It certainly doesn't prove it, but when I finished looking at 2014, I wondered, did this hold across other seasons as well?

I had 16 weeks of play by play data from 2013, so I decided to look at that as well and see if what I saw in 2014 was an anomaly.

You can be the judge.

Below is an image from my last post, the frequency of injury stoppages by offense/defense and quarter:

Now, here's the same chart, but for my 16 weeks of the 2013 regular season

I'd say those are similar! We observe the same pattern, injuries increase as the game goes on, and almost entirely on the defensive side of the ball.

Now, below is the scatter plot that illustrates an offense's plays per game against its opponent's rate of injury. This had by far the most significant correlation of all the game situations we examined - and it's the only situation where teams would benefit from faking injuries.

So we saw a correlation of 0.39 - whereas other game situations didn't have anything close to that high.

How about 2013?

Once again, a pretty interesting positive correlation.

And, as in the 2014 analysis, there was nothing close to a similar correlation in the other game scenarios.

So now we have two years of analysis, both of which show the same patterns in the data.

When teams run more offensive plays, the defenses they face need injury stoppages more frequently.

Either you attribute this to defenses being out of shape/unprepared and thus more likely to get fatigued and hurt...or you're like me and assume on the margins some players fake an injury occasionally to get a breather.

I'm willing to listen to arguments for the former, but I'd say if you think Bill Belichick hasn't thought about it, that seems unlikely

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