Sunday, December 18, 2022

AP Defensive Player of the Year Perspective Using EPA and WPA as a Guide

By Nick Webster 
Maxx Crosby

Aaron Donald’s lack of dominance has contributed to a wide-open AP Defensive Player of the Year (DPOY) contest for 2022.  We’ll leave it to later whether Donald is showing signs of age and falling off – but for the first time in years, he’s not in the DPOY conversation.  

As of now, Las Vegas rates the DPOY odds as Micah Parsons, Nick Bosa, Chris Jones, Matthew Judon, and Maxx Crosby ranked in that order. 

DPOY is always difficult because we’re comparing players with very difficult skill sets. So and so has more sacks, so and so has more stuffs, more passes defensed, more picks, etc., and that can be useful. But another way to view this is through EPA and WPA.  

For the non-statheads, EPA is expected points added and WPA is win probability added. On any given play there is an expected number of points to be scored before the play and after the play, EPA measures the difference.  

Remember the Steelers-Cardinals Super Bowl?

James Harrison intercepts a pass on the goal line, the expected points before the play was nearly 7, after he scores, it is now -7, so the EPA is -14. Harrison turned an expected 7 into a -7 points.  

You do the same thing with WPA but the scale is from 1 to -1 and it changes based on WHEN the play happens. 

The Harrison play on the second or third play of the game may have very little WPA but at the end of the game – if it’s close – would have a high WPA. WPA is about “leverage” and how important was the situation in which the player made the play.
That said, let’s look at this year's DPOY game through the EPA/WPA lens.  

Most feel Micah Parsons is likely to win, Vegas says so, but what do the numbers say?

We have sacks and we have lots of other stats we can measure with EPA/WPA and with that we can determine how much these players impact the likelihood that the other team will score and ultimately win.

Many will be surprised to know that based on EPA and WPA Maxx Crosby is the most impactful defense of the year on both fronts.

This chart is sorted in order of EPA—

However, Crosby still has little chance of winning which is too bad. He's having a great season. 

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