Data that Deceives

 

Yesterday, an interesting tidbit was highlighted in turfshowtimes.com “Rams News…” Mathew Stafford had the highest 3^rd down conversion rate in the NFL.  The Rams touted Stafford “as the single most productive quarterback when it comes to converting on third downs.”  Stafford deserves kudos for his 2021 accomplishments, this one included.  However, while this is a useful metric indicative of past success, it has been shown for a long time it is not a repeatable skill. 

Performance on third down plays a huge role in team success... Third down success keeps the offense on the field and the opponents defense reeling. It clearly maintains drives for the inevitable goal of scoring. While it’s an important aspect of evaluating a quarterback's past performance relative to wins, it's not a skill. QB’s who do well on third down over the long term are the quarterbacks who also do well on first and second downs.

Football Outsiders has shown that teams that play significantly better on third down than they do on first and second down in a given year tend to see that third-down performance regress back to their performance on the first two downs in the following season.  Similarly, teams that underperform on third down tend to see a positive bump the year after.  Football Outsiders refers to this as “the 3^rd down rebound effect.”  One needs to evaluate overall quarterback success regardless of down.  Weighing 3^rd down performance to forecast future 3^rd down success is not appropriate prognostication.

Eagles Lessons: Where have we seen this before?  In the Eagles Super Bowl (2017) season, Carson Wentz was a 3rd and long magician- 44-for-71 (62%) for 727 yards, 7 TD’s,  117.5 passer rating.  On 3^rd/4^th & short, he was the NFL’s best (20-of-24 {83%} for 186 yards, 5 TD’s, 138.4 passer rating). 

Wentz’s third down success in 2017 hid an uncomfortable truth… Before third down, Wentz was a bottom 10 starter, with an EPA/play (EPA, Expected Points added, is a key stat in Football Analytics) that was 23^rd.  His great success on 3^rd downs delivered an MVP-like season, but, as Football Outsiders explains, it was not repeatable!

2020 was a similar aberration for Wentz statistically as things fell apart around him and he played poorly.  His other seasons, including 2018-2019 and his 2021 season with the Colts have been “OK.” 

Carson Wentz fooled us in 2017.  His subsequent injuries and reversion to the norm statistically on 3^rd downs pulled his play into the middling area for QB’s.  Wentz will not be a world beater for the Commanders.  He’ll be an “OK” QB, likely better given health and the right players around him. 

As for Stafford?  He’s a good QB, but expect similar regression to the mean on 3^rd down success next year!