Introducing Red Zone Expected Value & 7 Quarterback Touchdown Regression Candidates
Touchdowns are thought to be the most volatile stat in football, and there is data to support that theory. On a per-game basis, no stat has a lower year-to-year correlation for quarterbacks than touchdowns. Just because a stat is inherently erratic, though, doesn’t mean that it isn’t predictable.
The fact that touchdowns usually don’t carry over from one year to the next suggests that any statistical outliers are likely to regress to some mean -- either to the league average, or to a player’s individual average. By examining two stats -- touchdown rate and red zone touchdown rate -- that have shown a tendency to regress to the mean, we can infer which quarterbacks are likely to see a significant change in their touchdown totals from 2015 to 2016.
Introducing Red Zone Expected Value
Another indicator of players that didn’t produce as expected in the touchdown column is a metric that I built called Red Zone Expected Value (RZEV). RZEV calculates how many points a player should have generated from touchdowns based on the yard line that a play started.
A pass play that starts between the opponent's 16 and 20 yard line, for example, has an 11.7 percent chance of scoring a touchdown, resulting in an expected value of 0.70 points scored per pass attempt (6 points per touchdown * 0.117), whereas a pass play that starts inside the five yard line has a RZEV of 2.59 (43.2 percent touchdown rate).
Here are the expected values for all red zone pass attempts:
|Starting Yard Line||% Chance of a TD||EV of a Pass Attempt|
After compiling every red zone pass attempt for every quarterback in the league, I calculated each passer’s RZEV and compared that number to the actual points that they generated from red zone touchdowns in 2015. The differential in those numbers will highlight signal callers that scored more often or less often than they should have in the red zone.
Negative Touchdown Regression Candidates
League Average Touchdown Rate - 4.6%; League Average Red Zone Touchdown Rate - 23.8%
2015 TD Rate - 7.1%; Career TD Rate - 4.8%
2015 Red Zone TD Rate - 34.2%; Career Red Zone TD Rate - 25%
RZEV - 103.6 points; Actual points from Red Zone TDs - 156
Since the year 2000, 43 quarterbacks have thrown at least 200 pass attempts and achieved a touchdown rate of six percent or higher. Of the 39 quarterbacks that threw at least 200 times the following season, only two matched or exceeded their previous season’s touchdown rate. Collectively, those 39 quarterbacks saw their touchdown rate drop by an average of 1.9 percent.
Only 10 signal callers in the last 15 years have posted a touchdown rate as high as Cam Newton’s in 2015, and those passers saw their touchdown rate drop by a whopping 2.6 percent the following season. Even if Cam did make a big leap as a passer last season, his touchdown rate is virtually impossible to sustain, and his 2016 rate should be closer to his career average than what we saw in 2015.
Much of Newton’s touchdown fortune had to do with his success in the red zone. The Panthers’ quarterback threw a touchdown on over a third of his red zone attempts and only Tom Brady had more red zone points over expectation than Cam (+52.4). For Cam to match his touchdown totals from 2015, his volume would have to increase significantly, considering how far above expectation he performed in 2015.
2015 TD Rate - 5.4%; Career TD Rate - 4.4%
2015 Red Zone TD Rate - 35.5%; Career Red Zone TD Rate - 25%
RZEV - 114.6 points; Actual points from Red Zone TDs - 156
When it comes to touchdown rates, Matthew Stafford has been the model of mediocrity throughout his career, but in 2015 he achieved the eighth-highest red zone touchdown rate of any quarterback over the last 15 years. Going into 2016, the Lions’ quarterback will be without arguably the best wide receiver of our generation for the first time in his career, and Stafford’s past suggests that he can’t keep up his scoring pace from last year, even with Calvin Johnson on the field.
Stafford had the luxury of throwing the ball a lot from very close to the goal line. 26 out of Stafford’s 28 red zone touchdowns came from inside the 10 yard line and Detroit scored on 35 percent of their red zone pass plays, which was the highest rate in the league and 12 percentage points above the league average.
2015 TD Rate - 6.5%; Career TD Rate - 4.8%
2015 Red Zone TD Rate - 30.5%; Career Red Zone TD Rate - 22.6%
RZEV - 114.6 points; Actual points from Red Zone TDs - 162
For the second time in his career, Carson Palmer posted a touchdown rate over six percent. The problem is that there was a 10-year gap between those instances. Similarly, Palmer has never converted more than a quarter of his red zone attempts into touchdowns, but in 2016 he scored on over 30 percent of his red zone passes.
Only Newton scored more points on touchdown passes inside the red zone than Palmer, but based on the starting field positions of his red zone pass attempts, Palmer should have produced roughly as many red zone points as Jay Cutler.
With an aging Larry Fitzgerald, who also had an unsustainable touchdown rate himself last year, and one of the best young running backs in the league, Palmer may struggle to match his touchdown total from last season.
Positive Touchdown Regression Candidates
2015 TD Rate - 4.1%; Career TD Rate - 5.7%
2015 Red Zone TD Rate - 16.7%; Career Red Zone TD Rate - 26.7%
RZEV - 35.3 points; Actual points from Red Zone TDs - 24
Aaron Rodgers and Russell Wilson are the only active quarterbacks with a higher career touchdown rate than Tony Romo, and only five active signal callers have converted a higher rate of red zone passes into scores in their careers.
Last season, no quarterback threw for a touchdown rate or red zone touchdown rate further below their career average than Romo, who scored 1.6 percent and 10 percent below his career mean in those respective categories.
While some of that variance can be attributed to sample size (Romo played just four games in 2015), not having Dez Bryant fully available also hurt Romo’s numbers. With Romo and Dez both expected to return completely healthy in 2016, the Cowboys offense could mimic their 2014 numbers and Romo should return to form as one of the most efficient touchdown scorers in the league.
2015 TD Rate - 5.4%; Career TD Rate - 6.4%
2015 Red Zone TD Rate - 21.3%; Career Red Zone TD Rate - 26.1%
RZEV - 143 points; Actual points from Red Zone TDs - 138
Not having Jordy Nelson in 2015 obviously hampered the Packers offense, and this was especially evident in Rodgers’ scoring efficiency numbers, as the Green Bay quarterback turned in his lowest touchdown rate and second-lowest red zone touchdown rate since becoming the team’s full time starter.
Rodgers tied Blake Bortles for the most pass attempts in the red zone in 2015, but A-Rod ranked just 11th among quarterbacks in red zone touchdowns. As the most efficient touchdown scorer among active quarterbacks, natural regression and an offense at full strength points to Rodgers scoring at a much higher clip in 2016.
2015 TD Rate - 3.9%; Career TD Rate - 4.1%
2015 Red Zone TD Rate - 20%; Career Red Zone TD Rate - 23.1%
RZEV - 118.5 points; Actual points from Red Zone TDs - 90
Ryan Tannehill has never thrown touchdowns at a very high rate, but where he got very unlucky in 2015 was in the red zone, where his touchdown rate was the lowest since his rookie season. When you consider where Tannehill was throwing from in the red zone, it’s even more surprising that he didn’t find the end zone more often.
Over 57 percent of Tannehill’s red zone attempts came from inside the 10 yard line and 31 percent came from inside the five, both of which were the highest percentages in the league. Despite massive volume very close to the goal line, the Dolphins’ quarterback ranked 19th among quarterbacks in red zone touchdowns, and scored almost 29 points below RZEV.
The fact that Jarvis Landry, who doesn’t fit the prototypical dominant red zone receiver mold, was Tannehill’s main red zone target (32 percent of team red zone targets, 39 percent inside the 10) could explain some of that inefficiency. New head coach, Adam Gase, is much more likely to use a big-bodied receiver like DeVante Parker near the goal line, which could result in a big boost to Tannehill’s scoring rate.
2015 TD Rate - 4.3%; Career TD Rate - 4.7%
2015 Red Zone TD Rate - 15.8%; Career Red Zone TD Rate - 23.9%
RZEV - 113.6 points; Actual points from Red Zone TDs - 66
For most of Jay Cutler’s career, he’s had the comfort of knowing that he could lob it up to either Brandon Marshall or Alshon Jeffery near the goal line. That wasn’t the case in 2015 and the numbers reflected it, as Cutty threw for the lowest red zone touchdown rate of any qualifying quarterback last season.
Even more telling of the Bears’ lack of a red zone threat last season was Cutler’s red zone touchdowns compared to RZEV. Cutler scored almost 48 points below expectation, the most points below RZEV by a huge margin -- no other quarterback scored more than 29 points below expectation.
With Alshon and Kevin White available, Chicago will roll out a receiving corps much closer to what Cutler is used to and that should result in a noticeable bump in red zone scores for the Bears’ quarterback.