Old Mother Hubbard 2012: Detroit Lions Team Needs

>> 1.17.2012

pantry_overflowing

Old Mother Hubbard 
               Went to the cupboard,
               To give the poor dog a bone:
             When she came there,
              The cupboard was full of talented young football players,
             which was pretty awesome.

Yes, it’s time once again for The Lions in Winter’s annual roster analysis/team needs thing, Old Mother Hubbard. Last season’s edition added Pro Football Focus grades and statistics, plotting them on radar charts for easy understanding. This was well received.

I highly value PFF data, they do fantastic work that nobody else is doing. As I said, if I had the time to grade out every Lion on every snap of every game for these breakdowns I would—but PFF already did, so I stand on their shoulders.

However, I don’t think PFF data is the only valuable way of describing a player or season. I’m a big fan of the work Brian Burke does at Advanced NFL Stats, and I’m going to be including (at least) his  Win Probability Added stat, WPA. Burke explains WPA here:

Stats are tools, and each tool has its own purpose. WPA is what I call a narrative stat. Its purpose is not to be predictive of future play or to measure the true ability of a player or team. It simply measures the impact of each play toward winning and losing.

WPA has a number of applications. For starters, we can tell which plays were truly critical in each game. From a fan’s perspective, we can call a play the ‘play of the week’ or the ‘play of the year.’ And although we still can't separate an individual player's performance from that of his teammates', we add up the total WPA for plays in which individual players took part. This can help us see who really made the difference when it matters most. It can help tell us who is, or at least appears to be, “clutch.” It can also help inform us who really deserves the player of the week award, the selection to the Pro Bowl, or even induction into the Hall of Fame.

There are two main weaknesses with PFF grades—or perhaps I should say, two main characteristics you need to keep in mind when evaluating players with them. First is a strong pull towards the mean. Since an unremarkable play—a typically decent effort—gets graded as a zero, the fewer snaps a player has the more “average” he tends to look in his grades. PFF acknowledges this with a default minimum of 25% of available snaps, but it limits their utility in describing role players and backups.

The other factor is what I call a “consistency bias.” PFF’s grading system loves players who make consistently positive down-to-down impact, and tends to pooh-pooh “home run hitters” who make a couple big plays per outing. WPA works in the opposite way: it loves players that makes plays that win games. Between the PFF data and WPA, we should get a very complete picture of how strong the Lions’ roster is, relative to itself and relative to the rest of the NFL.

Number crunching is happening now; OMH's start going up by the end of the week.

7 comments:

Flamekeeper_Ty,  January 17, 2012 at 8:25 PM  

Stoked to write it! This is always fun.

Angus Osborne,  January 17, 2012 at 9:10 PM  

Hoody hoo, can't wait.

Cramer,  January 18, 2012 at 2:35 AM  

Ty,

I just want to let you know that the analysis you did last year was my first time reading you and it was so far beyond what I am used to that I have continued to follow you on your blog and bleacher report sense. Your statistical approach and in depth break downs appeal to this engineer in a way that few other football people online can. I cant wait to read this and keep up the good work!

Adam,  January 18, 2012 at 7:16 AM  

One of my favorite posts for the offseason!

PA Lions Fan,  January 18, 2012 at 1:05 PM  

Ty, Can't wait for OMH. Perhaps at the end you could do a summary called "From Good to Great".

KlfhWQL,  January 21, 2012 at 11:23 PM  

Love the site. Also- it's the end of the week...

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