Saturday, September 19, 2020

NFL Cornerback Comparison 2019-2020

 Cover Men

Cornerback is one of the most impactful positions on a football field.  A great one can eliminate the opponent's best receiving weapon and a bad one is a liability that can throw the entire defense into chaos.  For the 2020 NFL season, I will update three metrics I find interesting in looking at CB play:
  1. Total Targets/Total Snaps ("Attack Ratio") - The lower the better.
  2. Total Yards Against/Total Snaps ("Bleed Ratio") - The lower the better.
  3. Total Interceptions/Total Touchdowns ("Burn Ratio") - The higher the better.
Each metric is stated as a Z-score (# of standard deviations from the mean) which is then averaged for a final score.  The player data is aggregated on a team basis. 

2019 Cornerback Statistics 


The above reflects the 2019 results for starting CBs.  Their performances were aggregated by team to provide baseline metrics for comparison to 2020.



Notes:
  • There are only 31 CB units in the table above because none of the starting CBs for MIN had material statistics in 2019.
  • The 2019 numbers reflect the individual numbers of CBs on the 2020 squads for each team.
  • It is said the NFL is a parity league and the numbers show that is the case with only one team's CBs showing performance beyond one standard deviation above the mean (PIT).
  • CAR, while establishing the bottom border, still remained within 1 standard deviation of the mean.  
  • Attack Ratio
    • LAC was #1 in terms of ATTACK ratio meaning teams targeted their CBs the fewest times per snap.
    • PHI was dead last and anyone watching knows they had not a lot of household names on the corners.
  • Bleed Ratio
    • PIT was #1 as their CBs allowed the fewest yards per snap in 2019.
    • CAR has a rough time of it giving up the most yards per snap. 
  • Burn Ratio
    • NWE not only topped the list but they had the highest Z-Score in any of the three categories but having the highest TD to INT rate.
    • ATL was pretty deficient in this category with the worst Z-Score of any team in any category.  

2020 Season

I will update the week to week numbers related to the three metrics (Attack, Bleed and Burn ratios) and compare them to each team's 2019 numbers (above).
Since we only have Week 1 data, we will start with the "Bleed Ratio" Total Yards/Total Snaps compared to 2019 and bring in the other metrics in the coming weeks as we get more data.


Blue lines represent 2019 performance and Orange, Week 1 of the 2020 season.
  • Better than Expected  (Positive Orange line higher than Blue line)- BUF, DEN and TEN
  • Clearly Worse than Expected  (Negative Orange line lower then positive Blue line) - JAX, KC, LVR and PIT
  • Everyone else is not far off expectations with the exception of LAC and NWE who are both on the right side of the line but not show a drop off from last season.  But we have only one game under our belts.

Here's the NFC:



  • Better than Expected  (Positive Orange line higher than Blue line)- CAR, CHI, DET and NOR.
  • Clearly Worse than Expected  (Negative Orange line lower then positive Blue line) - LAR and SEA.
  • Everyone else is not far off expectations with the exception of ATL which was expected to struggle based on last year but has fared worse than expected in Week 1 and NYG who, while still below the line, are much improved in terms of their Bleed Ratio.  

Again, with the less than ideal circumstances this offseason, the early numbers are really just for tracking purposes for now.  Once we get past Week 3, it will be interesting to see how the teams perform to 2019.  As the season progresses, we will add data and charts to reflect the Attack and Burn ratios.

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Looking at NFL QB risk/reward metrics.  Is your team's QB making the right decisions?  https://boombearfootball.blogspot.com/2020/07/nfl-qb-riskreward-based-on-2019-numbers.html


Check out the full 2020 NFL draft review for value picks and need fulfillment!  https://boombearfootball.blogspot.com/2020/04/nfl-draft-2020-whos-screwed-recap-of.html


The Fourth Annual All-Social Media Top 100 List for NFL Draft prospects is posted...check it out here!  Who did your favorite DraftTwitter football fanatics select?  

Find out here!  https://boombearfootball.blogspot.com/2020/04/boombearjrs-fourth-annual-all-social_22.html


Monday, September 7, 2020

NFL QB Risk/Reward Based on 2019 Numbers

Risky Business

It is said the best attribute a quarterback can have is a short memory.  After a bad play, it's best to look toward the next one instead of carrying a negative mindset around the rest of the drive or even the rest of the game.  And that negative mindset can interrupt the muscle memory built over countless hours of practice when a QB starts second guessing; he will then become more risk averse.  The difference between QB success and failure can come down to just a few throws a game so it's crucial to remain balanced in terms of maintaining the right amount of risk to justify the resultant rewards.

Let's take a look at NFL QBs from 2019 (per www.pro-football-reference.com) to attempt to understand a bit more about how NFL QBs risk habits relate to their overall performance by looking at the following:
  1. Errors - those made by the QB exclusively and errors that should not be attributed to the QB.
  2. Risk/Reward - analyzing Intended Air Yards and Completed Air Yards.
  3. QB Rating
  4. Understanding if the passing game relied more on the QB or Receiver


Errors

Two types of "errors":

  • Own Errors:  Negative errors.  The total of Interceptions (Int), Fumbles (Fmbl), Batted Balls (Bats) and Bad Throws.  
    • The total is compared to the number of Attempts (Att) with each player graded based on their distribution relative to the top score awarded a 100 and an "average" grade of 70.

Observations:

  • Although Drew Brees made the fewest Own Errors, Derek Carr was a fairly close second earning a grade of 95.8.
  • Not surprisingly, Jameis Winston's league leading 30 INTs and 124 "bad throws" put him at the bottom of the list. 
  • Four non-playoff teams had QBs in the top 10:
    • #2 OAK/LV - Carr
    • #4 DAL - Prescott
    • #8 - ATL - Ryan
    • #10- LAC - Rivers
  • The of the 12 QBs with the highest Own Errors grade, there were three playoff teams represented:
    • #30 BUF - Allen
    • #22  PHI - Wentz
    • #21 BAL - Jackson
  • Both the Offensive MVP (Jackson) and Rookie of the Year (Murray) had below average Own Errors grades.

  • Other Errors:  Non-QB driven errors.  The total of Throwaways and Drops divided by Attempts.  (I'm sure some would argue some throwaways are the QBs fault but not for this analysis).




Observations:

  • Although Stafford had a rough year in terms of Own Errors (#28 overall), his receiving corps did a nice job getting open and holding on to the ball.
  • Allen, who was #30 in Own Errors didn't have a whole lot of help from his guys.
  • Looking at Rodgers at #24 with a failing GB grade in Other Errors makes their draft even more painful with a 6'2" TE as their only receiver selected.
  • Brady being near the bottom of the list at #31 and TB being at #14 despite Winston under center makes me very, very scared of the Bucs this year. 

Risk/Reward

Now that we can see how each QB and his team stand in terms of errors, let's try to see what we can surmise once we look at the degree of risk a QB is willing to take to gain a yard. 

Intended Air Yards:  Air yards on all pass attempts, whether complete or incomplete.
Completed Air Yards:  Yards that a pass traveled beyond the line of scrimmage before being caught.

Comparing the average intended air yards to the average completed air yards and we see how much risk a QB is willing to take to get one yard, represented by "Risk Reward (IAY/CAY)".

The average CAY is 4.0 yards and so not to reward QBs who do not make this threshold, the rankings were ordered based on CAY > 4.0 then Risk Reward



Observations:

  • Drew Brees has by far the lowest Risk Reward ratio where he risked only 1.21 yards for each passing yard gained.
  • Interestingly, the top 10 was split 50/50 between playoff and non-playoff teams with Matty Ice holding the #2 spot. 
  • Rudolph had a pretty rough year all around but his highest Risk/Reward rating shows the ball well over twice as far as the overall #1 Brees to get the same yard.
  • Rodgers is second to last, not far from Rudolph.  So is the conclusion these two are similar?  Let's try to rap this up to see what we can determine.

Who's Responsible?

Now that we understand QB errors, Other errors and Risk Reward, let's see if we can draw any conclusions:

Key to Colors


Looking at the Ratings from Left to Right we assign responsibility for each teams' success in the passing game.

Observations:

  • Brees takes minimal risks (Highest Risk/Reward grade) has a high QB rating (converted to our base 100 system), his Receivers Own Errors are > 1 Standard Deviation from the mean but his Own Errors are greater than 2 Standard Deviations from the mean.  
    • As much support as he gets from this players, Brees is clearly driving the results.
  • Looking at Matt Stafford, he had an above average Risk Reward Grade so he's not afraid to air it out to get his yards and while he had a strong QB rating, his Own Errors were below average.  Conversely, his Receivers Own Errors were top of the league, performing two levels above their QB.  
    • Based on this, their success was driven by the Team more than Stafford. He was dinged up a lot last year so if he's 100%,  we would expect him to be more of a contributor to the Lions' success. 
  • Poor Derek Carr took a lot of heat last year but when you take a look at his numbers, he has an above average QB rating, he is near the tops in assessing Risk/Reward and he is disciplined in terms of Own Errors.  
    • The Team was near the bottom of the heap in terms of Errors performing a whole 3 levels below Carr.  Maybe the critics are too harsh on him?
  • QBs with above average metrics and below average Team metrics:
    • Cousins
    • Prescott 
    • Mahomes
    • Carr
    • Brady
    • Rodgers 
  • QBs and Team both have above average error metrics:
    • Ryan
    • Tannehill
    • Wilson
    • Watson
    • Rivers
    • Garappolo
    • Trubisky
  • QBs with below average metrics with above average Team metrics:
    • Stafford 
    • Fitzpatrick 
    • Winston 
    • Jackson
    • Keenum
    • Goff
    • Murray
    • Wentz
    • Jones
  • QBs and Team both have below average Error Metrics
    • Minshew
    • Dalton
    • Mayfield
    • Darnold
    • Josh Allen
    • Kyle Allen
    • Brissett

What's the Bottom Line?

  • Risk Reward has a fairly solid correlation with QB's Own Errors (Better performing Risk Reward/Better performing QB's Own Errors).  
  • QB Rating has a meaningful correlation with QB Own Errors and Risk Reward.
  • Others Errors have no meaningful correlation to the other metrics.  




































































































































Error Efficiency
The above gives context to the rate at which QB accumulate Owned and Unowned Errors on pass plays.  Does this mean Derek Carr was the best quarterback last year?  Of course not.  He was just the most conservative.  In fact, he was so conservative, he pretty much blew the curve. 
But what was the price for being so conservative?  Let's take a look at other QB metrics to try to make sense of this all.




IAY and CAY


Intended Air Yard and Completed Air Yards are two measures to help us look at how far the average passing attempt is compared to the average distance for completed passes. 




For context the top five in terms of IAY were:

  1. Matt Stafford: 10.6 IAY (29.4% farther than the 8.2 IAY peer group average [PGA])
  2. Jameis Winston: 10.4 IAY (26.9%)
  3. Ryan Tannehill: 9.5 IAY (15.9%)
  4. Russell Wilson: 9.4 IAY (14.7%)
  5. Dak Prescott/Josh Allen: 9.3 IAY (13.5%)
The above represents an aggregate record of 46-35-1 and 3 2019 playoff teams (one making it to conference championship game).


The bottom 5 in terms of IAY were:
  1. Drew Brees: 6.4 IAY (-21.9% shorter than the PGA)
  2. Jimmy Garoppolo: 6.5 IAY (-20.7%)
  3. Derek Carr: 6.6 IAY (-19.5%)
  4. Joe Flacco: 6.7 IAY (-18.2%)
  5. Case Keenum: 6.9 IAY (-15.8%)
The players above represent an aggregate 43-37 record and two playoff teams (one making it to the Super Bowl).


For Completed Air Yards:
For context the top five in terms of CAY were: