As a follow-up to my piece on the metrics behind Northwestern’s QBs, I wanted to write up something highlighting some of the stats behind NU’s secondary (I’ve been sitting on the data for a while, but now that I’ve graduated NU and look for a job, I have the time to type these things up). This is the last of the postable data so I won't span the FanPosts anymore.
I’ll preface this by saying stats on corners and safeties are the hardest to collect and analyze outside of the offensive line. You have to make determinations on who was targeted, what the coverage was, and collect objective results. They are difficult to analyze, but we’ll do our best. Since I have a nice mix of data on safeties and corners, I’ll split the sections up by player. As a note, I’ve spent most of my time working on draft stats, so I’ll be doing a lot of comparisons to draftable players and averages. We’ll start off on a positive note with Ibraheim Campbell in this one.
Ibraheim Campbell Could Be a First Round Draft Pick
I’m just going to post the full chart here and explain the stats as I go along
- Campbell’s stats are intriguing. We’ll start with perhaps the most interesting of them all, Burn Rate. That is, it approximates the quality of coverage by dividing the number of times the player was beat by their total targets. You’ll notice that Campbell was only burned on 27.9% of all targets. To put that into context the average safety drafted in the first three rounds of the draft will have a burn rate of around 45-50%.
- Campbell’s burn rate of 27.9% was second lowest in the entire BCS among all defensive backs last year. There are obviously many variations in defensive schemes, but this number is still impressive. Both Mark Barron and Harrison Smith, first round S, had similarly low burn rates
- For Passes Defensed we take a look at how often the players knocked down or intercepted the ball when they were targeted by the opposing QB. The 3.31 notes that Campbell knocked down 1 ball for every 3.31 passes or approximately 30% of balls thrown his way. The average among high-level safeties is about 20%, so Campbell did an excellent job playing the ball as a sophomore.
Nick VanHoose Looks Promising
- Referencing the numbers above, we can see that VanHoose’s burn rate was around 47.4%. This would be on the high end for a drafted corner, however for someone starting their freshmen year it’s excellent. Often new corners with talent tend to get burned a lot, so it’s encouraging to see that’s not the case. Assuming he could lower that down to 42-45%, you could start to view him as a top-tier CB in the Big Ten.
- For a corner, his ability to break up passes is very solid. His rate of 1 PD to every 5.7 passes would be about average for a top-tier CB. This combined with his 3 interceptions this past year bodes well for a ball-hawking corner.
- While his snaps per target looks low compared to the other players on the chart, you have to remember he’s a CB. Being targeted once every 5.5 snaps is just about what you’d expect. The stats all seem to indicate that he was at worst an above-average corner as a freshman. As an NU fan you have to be excited about what VanHoose will bring to the table in the future.
Daniel Jones Was a Bit Shaky
- I’ve thrown in Jared Carpenter and Quinn Evans in for comparison’s sake. I won’t analyze them since they’re no longer relevant, but you can make conclusions as you’d like.
- The "Impact" and "Missed" on the right side refer to impact tackles and missed tackles. Impact tackles consist of tackles behind or within 2 yards of the LOS and tackles in clutch (3rd and short, goal line) situations. Missed is what you’d expect.
- Players that didn’t have enough snaps last year to qualify were left out, Davion Fleming, etc.
There is a lot of variance in secondary stats due to different coverages, opposing QB play, and many other factors – so take these stats as a way to quantify what you’ve seen rather than gospel. I won’t go into correlations and whatnot, but I will say from quite a bit of experience that DBs that are above-average in snaps/target, passes defensed, and burn rate tend to be highly successful in college and drafted well. Take that and the stats as you may.