Hokepoints Finds Nothing in Assists Comment Count

Seth

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No Cam you don't get points for setting up Morgan's one-timer.

Still playing with the big spreadsheet of stats. Sometimes I glom onto something interesting and sometimes, like today, I waste a lot of time to realize a stat they track has no bearing on play at all, and then I have to write my article, and then Comcast manages to make me wish Greg Robinson was my internet provider and, well, that's my excuse.

While Ace was writing the MSU preview for this year's HTTV (you are welcome to pester Brian to start the kickstarter) I was feeding him various kill-me-now defensive stats that showed State was really good at defense last year. One thing we pulled up was a larger percentage of tackles that were assisted, something MSU seemed to share with other teams.

This does make sense if you think of plays that are good for a defense, e.g. a lot of bodies going nowhere at the point of attack, versus how long gains tend to end. Likewise you'd expect the position of the player to make a difference just because of the variance in amount of space between him and the next defender. A typical distribution of tackles was as follows:

Position Group % of Total % Solo
Defensive Line 24% 51%
Linebackers 35% 55%
Defensive Backs 41% 65%

Noise in the data: I built this from complete game stats, not play-by-play, so I couldn't separate special teams plays, etc. I did re-categorize a bunch of players listed at incorrect positions but I couldn't catch all of them. Tweener positions also throw things off: a WDE to a 4-3 under team is an outside linebacker to a 3-4 squad, 3-3-5 teams call the Spur a safety, Jake Ryan puts his hand down in the nickel, etc. There's tens of thousands of tackles in the above percentages but as we get into teams keep these inconsistencies in mind. FCS teams and stats accumulated against them were removed.

Who's doing the tackling? So in the above table defensive linemen have marginally more assisted tackles than linebackers, and both have significantly more tackles assisted than defensive backs. If tackle assists mean anything other than "more forward players are doing the tackling" we can see that by testing whether the % of tackles accrued by the front 7 or % of tackles assisted have a closer relationship to tempo-free defensive efficiency.

Tackles and assists

So yeah, it's where the tackle takes place, not some mystical ability of great defenses to get more people to arrive at the ball at the same time. And neither is that strong of a correlation. Sorry, every platitudinal defensive coach ever.

So how'd we do?

The Big Ten ranked by fewest yards ceded per play:

Team % by DL/LBs Rk % Solo Rk Def YPP
Michigan State 59% 8 48% 2 4.0
Iowa 64% 2 50% 4 4.6
Wisconsin 65% 1 63% 11 4.7
Maryland 62% 5 56% 6 5.1
Nebraska 58% 10 60% 9 5.2
Ohio State 56% 11 62% 10 5.3
Michigan 62% 4 56% 5 5.3
Penn State 60% 7 59% 7 5.3
Northwestern 61% 6 59% 8 5.5
Minnesota 54% 13 67% 13 5.7
Rutgers 63% 3 50% 3 5.7
Purdue 55% 12 71% 14 6.2
Illinois 52% 14 45% 1 6.7
Indiana 58% 9 66% 12 6.7

That Illinois and Michigan State are the top two teams at getting assists on their tackles says tackle assists aren't a thing. Rutgers was great at getting linebackers to the ball, but not until lots of yards had been accrued. Northwestern's a good study in this: in 2012 they had safety Ibraheim Campbell racking up Kovacsian solo tackle numbers, but in 2013 they had greater contributions from up front…with little increase in productivity.

I don't even see much in the way of stylistic preferences coming through. Michigan and Nebraska and Ohio State I believe (gleaned from what their coaches say at clinics mostly) are "spill" teams—they try to occupy blockers so a free hitter can make his way to the ball. Michigan State and Wisconsin and Penn State, are the ones I believe were "gap" teams—every defender has a gap he's responsible for closing.

So…okay, this stat means nothing. Good to know I guess.

Comments

jwendt

May 13th, 2014 at 5:25 PM ^

Isn't tackle data notoriously unreliable?

I know in the NFL the coaches typcially update the tackle stats the day after the game.  This can lead to big inconsistencies in how things are counted between different teams.  Does anyone know if college works the same way?

Sports

May 13th, 2014 at 6:37 PM ^

Stupid question, but new to the board and all...

What's this httv that Ace is working on? I've seen it referenced a few times on the board and I'm curious,