Advanced Defensive Stats: Missed Tackles

I’ve written quite a bit about Chicago’s offense so far this offseason, but not as much about the other side of the ball. I want to change that in the next series of articles, using advanced defensive statistics from Pro Football Reference (PFR). We’ll start today by looking at missed tackles.

Baseline Rates

Let’s start by establishing a baseline for what is a normal rate of missed tackles.

I compiled all missed tackle stats from the PFR database for 2018 and 2019 (the only 2 years it has) and sorted them by position. In order to compare starters to starters and avoid rates skewed by backups, I assumed a base nickel package of 4 defensive linemen (DL), 2 linebackers (LB), and 5 defensive backs (DB). For all 32 teams over a 2 year span, this would mean roughly 256 DL, 128 LB, and 320 DB. This gave thresholds of 20 tackles for DL, 60 for LB, and 40 for DB.

Looking at those sample sizes, you can see the spread of missed tackle rates in the table below for each position group.

A few thoughts:

As you might expect, DBs miss the most tackles, while DL miss the fewest. That makes sense given where they usually make a tackle; it’s hardest to tackle somebody in space and easiest near the line of scrimmage.
Notice all three position groups have higher averages than medians, which indicates a few players who miss a bunch of tackles raise the average for everybody else. Thus when looking at the Bears players, I’ll compare what % range they’re in relative to their peers.

I should note that I looked at how these rates compared for individuals from 2018 to 2019 and found very little relationship overall. It’s hard to say with only 2 years worth of data, but it doesn’t look like missed tackle rate is super consistent from year to year. For the 128 players with at least 50 tackles in both 2018 and 2019, the correlation of 2018 rate vs. 2019 rate was only 0.073, indicating basically no relationship. However, 75 of those 128 were either above or below average both years (44 above, 33 below). So while there is definitely fluctuation, there might be some sort of trend consistency for many players. It’s really too early to say for sure.

Now let’s go through one position group at a time to see how Bears players fared in 2019.

Secondary

We’ll start with the secondary. The table below shows how all key players in Chicago’s 2019 secondary fared, as well as for players signed from other teams who will be on the Bears in 2020. I included some of the depth pieces, but not their rates, because the sample sizes are too small to mean much. I also included 2018 information for anybody who had it and color coded their percentile range to match the table above.

A few thoughts:

Based on the past few years, tackling is a potential problem to keep an eye on in the Bears’ secondary this year. Buster Skrine and Eddie Jackson are both consistently bad at it, and the Bears lost Prince Amukamara, who has consistently been an excellent tackler.
Chicago also swapped out HaHa Clinton-Dix for Tashaun Gipson at safety, which looks like a slight downgrade in the tackling department.
Missed tackles have also been a problem for Kyle Fuller in the past (he led the NFL in them in 2017 according to Pro Football Focus), and he struggled a bit there in 2019 after a solid 2018 showing.
Chicago’s depth pieces all seem to be okay at tackling, though they’re all small sample sizes that make it hard to draw too many conclusions. At the very least, none of them have any missed tackle numbers to make you concerned.
Jaylon Johnson was credited with a missed tackle rate of less than 6% in college last year, but we have no idea how well that will translate to the NFL. Still, that’s at least reason for optimism he might be able to replace Amukamara’s sure tackling.

Linebackers

Let’s move now to looking at the linebackers. The table below shows how all their key guys fared in 2019 and has all the fun quirks of the DB version above.

A few thoughts:

If you’re looking for Robert Quinn, I included him with the DL below because he played DE in Dallas last year.
Let’s start with the inside linebackers, where Danny Trevathan and Roquan Smith have both ranged from average to excellent over the last two years. The Bears should be just fine there, assuming both can stay healthy.
Depth is a bit more of a question mark with Nick Kwiatkoski and Kevin Pierre-Louis both gone; neither were particularly good or bad at missing tackles, which is perfectly fine for a backup. Likely 3rd ILB Devante Bond has been fine in that department over the last 2 years, albeit in a very limited sample size.
At OLB, Khalil Mack missed slightly more tackles than average fairly consistently the last 2 years. Leonard Floyd missed too many tackles, so the Bears won’t miss him on that front. Likely 3rd OLB Barkevious Mingo missed them at a similar rate to Floyd in 2018, his last year of playing meaningful defensive snaps.

Defensive Line

Finally, let’s look at the defensive line. The table below matches the ones above.

A few thoughts:

Sample sizes are smaller here, so it’s difficult to draw too many conclusions.
Roy Robertson-Harris had an awful tackling year in 2019 after being really good in 2018, which speaks both to the volatility of the small sample size and the fluctuation for this statistic that can happen year to year.
The only player who stands out as a consistently bad tackler is FA acquisition Robert Quinn. Quinn is technically more of an OLB in Chicago, but I included him here because he played DE in Dallas last year and Miami in 2018. I am curious to see how the Bears deploy him in 2019 since his skill set is quite different from that of Leonard Floyd, who he replaces. Floyd is a much worse pass rusher, but had coverage skills that gave the defense versatility. One thing both players had in common is that they consistently missed too many tackles.

What We Learned

It’s hard to put too much stock in these numbers without much evidence showing they are consistent from year to year. However, based on data from the last two years, it looks like Chicago’s front 7 should mostly be fine with missed tackles, with the notable exception of Robert Quinn. The secondary, on the other hand, has cause for concern in this department, as Eddie Jackson and Buster Skrine have consistently struggled with missing tackles and Kyle Fuller has had his moments as well.