Jump to content

Dawg Stats

  • entries
    16
  • comments
    21
  • views
    501

What the Hell is EPA?


Josh Hancher
 Share

There are so many stats across all the sports that represent advance stats or analytics.  Some  more obtuse than others.  I have always contended that advance stats are no different than the "eye test" in terms of judging or grading a football play or an entire  game.  The advance metrics are just putting a number on "explosive" offense or "stout" defense.  

EPA is one of the stats which we will reference a lot on this site as we break down not only the X and O's of the game, but add to the context with some advanced stats.  It stands for "Expected Points Added" and all you need to realize is that is give a number to each and every play's result based on:

  • Down
  • Distance
  • Field Position

An offense wants a high number for a play and opposite is true for the defense. A play has an "expected value" based on the conditions of the play.  A 3rd and 11 from your own 19 isn't expected to add as much "value"  as 2nd and 3 inside the opponent's red zone.  An offense that can convert a 3rd and 11 on a consistent basis will have a higher average EPA and will likely be one of the more explosive offenses.   Ohio State ranked #2 in Offensive EPA in 2021 and 1st in Points Per Game (46.3).  That is the picture of efficiency.  Georgia had a EPA average of .302 which was good for 17th in all of FBS (10th in Power 5) and 11th (38.7) in Points per game.  That points to efficiency, high valued plays tend to put points on the board.   Teams which you wouldn't expect to see, but had both high average EPA and PPG. 

  • UCLA 6th in EPA/33.4 PPG
  • Oregon State 8th EPA/ 34 PPG
  • Virginia 9th EPA/35.3 PPG

These teams were statistically efficient and put up a lot of points, but not elite in actual points.  Alabama was 19th in EPA but 3rd in PPG... that tells us that they depended on bigger plays, and made a lot of them.  A Heisman Trophy winner and two NFL 1st Rounders will do that.  But, it isn't ideal.  The 2021 Alabama (.299 EPA)  offense wasn't near as efficient in terms of EPA  as the 2020 (.450 EPA) truly elite offense.  

Check this video out and look at two TD scoring drives and see what "efficiency" looks like.  Both Georgia and Alabama scored TDs, but one offense took fewer plays and was more explosive.  

It is important to realize that field position plays an important factor in these numbers.  EPA inside your 40 has a neutral or negative value. Plays inside your opponent's 40 are expected to contribute to value.  Plays between the 40 are extremely important.   Here 8 of the highest EPA (non-scoring) plays from 2021.+

  • 3rd & 3 from UGA 32 Stetson Bennett pass complete to James Cook for 53 yds to the Mich 15 for a 1ST down 3.90 EPA
  • 1st & 10 from UGA 20 James Cook run for 67 yds to the Alab 13 for a 1ST down 3.847 EPA
  • 3rd & 15 from UGA 42 Stetson Bennett pass complete to Kenny McIntosh for 18 yds to the Mich 40 for a 1ST down 3.654 EPA
  • 2nd & 10 from UGA 30 JT Daniels pass complete to Daijun Edwards for 37 yds to the Misso 33 for a 1ST down 3.652 EPA
  • 1st & 10 from UGA 19 Stetson Bennett pass complete to George Pickens for 52 yds to the Alab 29 for a 1ST down 3.650 EPA
  • 1st & 18 from UGA 12 Kendall Milton run for 35 yds to the Geo 47 for a 1ST down 3.060 EPA
  • 3rd & 10 from UGA 35 Stetson Bennett pass complete to Adonai Mitchell for 15 yds to the 50 yard line for a 1ST down 3.016 EPA

 

These are 8 of the most "valuable" plays as calculated by EPA.  All were on the UGA side of the 50.  Three converted 3rd downs.  Two of  1st down plays resulted in 1st downs inside 30. And, needless to say that a 35 yard run behind the chains certainly has value.

With all that, here are the plays. Hit me up with any questions.  Here or on the Twitter.  

Edited by Josh Hancher

  • Like 1
 Share

3 Comments


Recommended Comments

Jim Wood

Posted

Quote

A play has an "expected value" based on the conditions of the play.

I have a question now that I understand this. You say this number is based on the down, distance, and field position. This make sense, but my question is who comes up with this number? Is the number for the entire sport of college football? How frequently do the numbers change? Is there a master source chart that all advanced stats folks use?

Link to comment
Josh Hancher

Posted

11 minutes ago, Jim Wood said:

I have a question now that I understand this. You say this number is based on the down, distance, and field position. This make sense, but my question is who comes up with this number? Is the number for the entire sport of college football? How frequently do the numbers change? Is there a master source chart that all advanced stats folks use?

I believe that it is based on how many actual points have been scored from the down distance and field position going back as long as they had play by play data

  • Like 1
Link to comment
Josh Hancher

Posted

Also, @Jim Wood  the EPA for a play’s  result is a product of “expected”  values. 

 

You are expected to gain 6.06 points on a 1st and goal from the 1. So, the result of the play being a TD + PAT would bet the .940 for that play 

If offense gets stuffed the expected points for the 2nd and G from 1 is 5.04

 

so that 1st down for no gain is -1.00 

 

  • Fire 1
Link to comment
×
×
  • Create New...