This is the ultimate one-stat summary for QBs (that we have so far). I haven't seen anything as well thought out as this for NFL stats. Very well done.
This is a great article and once again, you amaze me with your analytical skills. I was wondering how to access the EPA metrics that you cited from NFLFastR. There doesn’t appear to be a clear link to the data on their website and I just wanted to be able to see all the EPA stats from there.
Love the work, and your work in general! A few things have me wondering about some of the numbers, however. Let me preface by saying, yes, I'm a Bills fan; I acknowledge there's this weird defensiveness amongst Bills/Chiefs fans re: all things comparing their QBs; last, I believe Mahomes is the best QB in the world. Perhaps that's more so directed towards any replies, but anyways...
Like another reader commented, the "sacks" adjustment - do things like strength of opposing D Lines, quality of OLs (particularly those on the field at a given time when a sack occurs, to adjust for injuries), WR separation/coverage (I know PFF started tracking "perfectly covered plays" this year), etc, get taken into account? Allen's line has been objectively awful compared to, say Mahomes, and he's faced DLs like Tenn., Bal, KC, Mia, NYJ, & NE. Has Allen created his own pressure, of course, as has Mahomes, but surely Allen's escapability and plays made while avoiding pressure surely can't cause him to actually lose EPA from sacks when adjusted.
Secondly, the drops adjustment...Allen has constantly been let down by drops this year, inc dropped TDs, with his WRs leading the league in drops. How is his adjustment a third of Mahomes, and on the lower side as a whole?
Are things like YAC% vs air yards % accounted for? Are all TD passes treated the same? Or is their an adjustment for a 3 yd jet motion pop pass, or PA shuffle to a backside TE worth the same as 10+ or 20+ yard TDs?
Again, I acknowledge this sounds like salty Bills fan, but I'm just curious if you see any of these things as useful in trying to isolate solely the play of the QB, vs scheme/WRs/quality of opponents, etc. Thanks again man! Great stuff as always.
As you make adjustments I would expect the adj epa/play variance to fall relative to the raw epa/play variance. Theoretically we're removing noise from the raw? But in this analysis the variance is the same. I'm wondering if the issue could be that some of these adjustments are correlated. If you're treating them independently in that scenario, you could be piling onto qbs, or over-adjusting, by adding correlated adjustments. I'm terrible with statistics principles, so forgive my layman's explanation. Thanks for the content!
This is amazing work! I've been hoping for years to see QB luck quantified so it's awesome to finally see it. I eagerly anticipate the rest of this series.
I'm a bit confused by sack luck... for example when you subtract 11 points from Brady for sack luck, does that mean he held the ball long enough to take 11 EPA worth of extra sacks but his o-line bailed him out?
The one other variable I'd really like to see quantified is weather, or at least dome vs outdoor. It's undoubtedly easier to put up good EPA in a dome, and guys like Cousins and Goff look better than they should due to playing the majority of their games indoors. Conversely, AFCE and AFCN passers are hurt by playing almost all of their games outdoors and often in less than ideal conditions.
However, I still feel a quarterback like Jimmy G is not adjusted downwards enough. I’m only being half facetious to my favorite Jimmy truther.
Quarterbacks who don’t do much, but end up with completions to Kittle like we just saw (that was Purdy, but coulda been Jimmy) might be impossible to quantify. Maybe we just need to ensure we use the eye test a little. Heresy I know. But im starting to believe it’s the only way to complete this seemingly unquantifiable puzzle.
This is the ultimate one-stat summary for QBs (that we have so far). I haven't seen anything as well thought out as this for NFL stats. Very well done.
This is a great article and once again, you amaze me with your analytical skills. I was wondering how to access the EPA metrics that you cited from NFLFastR. There doesn’t appear to be a clear link to the data on their website and I just wanted to be able to see all the EPA stats from there.
Awesome stuff Kevin. In addition to adding receiver skill, I would love to see adjustments for play callers. Some ideas to test:
Early down pass rate
ADOT
Play action rate
Pre snap motion rate
And for team rushing success:
Rush success rate
Rush EPA
If you adjust for the above and Jimmy G is still top 5, film twitter might finally have to respect him!
I agree with Mr Conner. This absolutely fantastic stuff!
Love the work, and your work in general! A few things have me wondering about some of the numbers, however. Let me preface by saying, yes, I'm a Bills fan; I acknowledge there's this weird defensiveness amongst Bills/Chiefs fans re: all things comparing their QBs; last, I believe Mahomes is the best QB in the world. Perhaps that's more so directed towards any replies, but anyways...
Like another reader commented, the "sacks" adjustment - do things like strength of opposing D Lines, quality of OLs (particularly those on the field at a given time when a sack occurs, to adjust for injuries), WR separation/coverage (I know PFF started tracking "perfectly covered plays" this year), etc, get taken into account? Allen's line has been objectively awful compared to, say Mahomes, and he's faced DLs like Tenn., Bal, KC, Mia, NYJ, & NE. Has Allen created his own pressure, of course, as has Mahomes, but surely Allen's escapability and plays made while avoiding pressure surely can't cause him to actually lose EPA from sacks when adjusted.
Secondly, the drops adjustment...Allen has constantly been let down by drops this year, inc dropped TDs, with his WRs leading the league in drops. How is his adjustment a third of Mahomes, and on the lower side as a whole?
Are things like YAC% vs air yards % accounted for? Are all TD passes treated the same? Or is their an adjustment for a 3 yd jet motion pop pass, or PA shuffle to a backside TE worth the same as 10+ or 20+ yard TDs?
Again, I acknowledge this sounds like salty Bills fan, but I'm just curious if you see any of these things as useful in trying to isolate solely the play of the QB, vs scheme/WRs/quality of opponents, etc. Thanks again man! Great stuff as always.
As you make adjustments I would expect the adj epa/play variance to fall relative to the raw epa/play variance. Theoretically we're removing noise from the raw? But in this analysis the variance is the same. I'm wondering if the issue could be that some of these adjustments are correlated. If you're treating them independently in that scenario, you could be piling onto qbs, or over-adjusting, by adding correlated adjustments. I'm terrible with statistics principles, so forgive my layman's explanation. Thanks for the content!
This is amazing work! I've been hoping for years to see QB luck quantified so it's awesome to finally see it. I eagerly anticipate the rest of this series.
I'm a bit confused by sack luck... for example when you subtract 11 points from Brady for sack luck, does that mean he held the ball long enough to take 11 EPA worth of extra sacks but his o-line bailed him out?
The one other variable I'd really like to see quantified is weather, or at least dome vs outdoor. It's undoubtedly easier to put up good EPA in a dome, and guys like Cousins and Goff look better than they should due to playing the majority of their games indoors. Conversely, AFCE and AFCN passers are hurt by playing almost all of their games outdoors and often in less than ideal conditions.
Great work as usual. Just top notch.
However, I still feel a quarterback like Jimmy G is not adjusted downwards enough. I’m only being half facetious to my favorite Jimmy truther.
Quarterbacks who don’t do much, but end up with completions to Kittle like we just saw (that was Purdy, but coulda been Jimmy) might be impossible to quantify. Maybe we just need to ensure we use the eye test a little. Heresy I know. But im starting to believe it’s the only way to complete this seemingly unquantifiable puzzle.