The data below, taken from Pro Football Focus’s “Premium Stats,” are for the QBs in the NFL who have taken at least 75% of the offensive snaps for their teams this year. The data pertain to team and QB variables related to sacks, which we know have been a problem for the Dolphins through the first five games in 2013. The Dolphins currently lead the league in sacks with 24.
The column headers in the table of data below refer to: 1) the QBs named in the table, 2) the total number of dropbacks they’ve had in 2013, 3) their average time to actually throw the ball (in seconds), 4) their average time they had to attempt to throw the ball (in seconds), 5) their average time to be sacked (in seconds), 6) their average time to scramble (in seconds), 7) the percentage of total dropbacks resulting in pressures, and finally, 8) the percentage of pressured dropbacks resulting in sacks.
In the third row from the bottom, entitled “Tannehill Z-score,” what we have is a standardized measure of how far above or below the league average Ryan Tannehill’s statistics are in these areas.
There are only two significant statistics to be found for Ryan Tannehill in that regard in my opinion:
1) The amount of time he’s had to attempt to throw the ball, which is 1.3 standard deviations below the league average, and which means he’s had significantly less time than the average QB to attempt to throw the ball (although that amount of time is just less than a quarter of a second [0.23 seconds], which is about as fast as the blink of an eye), and;
2) The percentage of pressured dropbacks resulting in sacks, which is 2.85 standard deviations above the league average, and which means he’s been sacked significantly more on pressured dropbacks than the average QB, and very much so. That difference is much more than just “the blink of an eye.”
However, contrary to what we might have previously believed, Ryan Tannehill is not being pressured on a greater percentage of his dropbacks than the average QB. He is also not being sacked more quickly than the average QB, and he is not taking any longer than the average QB to throw the ball or to scramble downfield (when he does).
It might seem sensible to close the book on the issue at this point and conclude that Tannehill’s greater percentage of sacks on pressured dropbacks is due to the smaller amount of time he’s had to attempt to throw the ball. It certainly isn’t due to the fact that he’s being pressured more often on dropbacks than the average QB, because he is not.
However, when we correlate 1) the time QBs have had to attempt to throw, with 2) the percentage of pressured dropbacks resulting in sacks (see the bottom row of the table), we find the correlation is -0.13, which means there is little or no relationship between the two variables.
In other words, QBs in the NFL are not being sacked more often because they have less time to attempt to throw the ball. Those two variables are unrelated, and therefore one cannot possibly cause the other. There’s a time-honored statistical maxim most people know that says correlation doesn’t equal causation, but it’s also the case that causation can’t happen without correlation. One variable cannot cause another if it isn’t correlated with it.
Additionally, when we correlate 1) the time QBs have had to attempt to throw, with 2) the percentage of total dropbacks resulting in pressures (see the row of the table above the bottom one), we find the correlation is 0.67, meaning that, contrary to what we might have expected, the more time a QB has to attempt to throw the ball, the greater percentage of the time he’s pressured on his dropbacks. So it can’t be said that Ryan Tannehill is being pressured because he has less time to attempt to throw the ball, when that isn’t the case for quarterbacks across the league.
What we also find by correlating some of the data is that, although the number of total dropbacks has a moderately strong correlation (0.40) with percentage of dropbacks in which QBs are pressured, total dropbacks is negatively correlated (-0.31) with the percentage of sacks in which the QB is pressured. This is an important distinction, because although it suggests that teams that run the ball less (i.e., those with more dropbacks) may be pressured somewhat more, it also suggests they are not sacked more. In fact they are sacked less.
(For any extreme stat geeks out there, please note that I also generated scatterplots for the above variables and investigated the possibility of quadratic relationships, of which there were none. The scatter appeared to be random in all cases.)
The take-home messages are the following three points in my opinion:
1) It’s inconsistent with the above data to believe that Ryan Tannehill’s greater percentage of sacks on pressured dropbacks is due to his having less time than the average QB to attempt to throw the ball.
2) It’s inconsistent with the above data to believe that Ryan Tannehill is being sacked more on pressured dropbacks because the team isn’t running the ball enough.
3) There must be another explanation for Ryan Tannehill’s much higher percentage than the league average of pressured dropbacks that result in sacks.
One possible explanation that’s consistent with the above data is that the amount and/or quickness with which Tannehill moves in response to pressure has been insufficient. This would explain why he’s pressured no more than, and no more quickly than, the average QB, but is sacked far more often than the average QB.
In other words, he may be doing a fine job of getting rid of the ball quickly when he does throw the ball, but a poor job of moving out of harm’s way when he doesn’t throw the ball.
This explanation fits very well with the above data in my opinion, in that Ryan Tannehill has had less time than the average QB to attempt to throw the ball, but more time than the average QB to actually throw the ball. In other words, when he senses pressure, he often gets rid of the ball quickly when he does throw the ball.
However, when Ryan Tannehill is pressured and he does not throw the ball, he’s much more likely than other pressured QBs to be sacked, thus illustrating the “lack of movement” hypothesis alluded to above. Obviously if he’s chosen (for whatever reason) not to throw the ball under pressure, the only other option available to him to avoid a sack is to move. What fits best with the above data is the idea that such movement under pressure on his part isn’t happening anywhere near sufficiently.
And of course this may be something he’s being coached to do, as well: to hang in the pocket and continue to visually scan downfield, despite whatever may be happening with regard to the pass rush.
The column headers in the table of data below refer to: 1) the QBs named in the table, 2) the total number of dropbacks they’ve had in 2013, 3) their average time to actually throw the ball (in seconds), 4) their average time they had to attempt to throw the ball (in seconds), 5) their average time to be sacked (in seconds), 6) their average time to scramble (in seconds), 7) the percentage of total dropbacks resulting in pressures, and finally, 8) the percentage of pressured dropbacks resulting in sacks.
Name | |||||||
Geno Smith | 186 | 3.24 | 2.89 | 4.63 | 5.52 | 42.2 | 22.8 |
Alex D. Smith | 219 | 2.92 | 2.57 | 4.11 | 4.82 | 31.5 | 17.1 |
Eli Manning | 248 | 2.79 | 2.7 | 3.81 | 4.1 | 41.1 | 15.7 |
Robert Griffin III | 187 | 2.77 | 2.59 | 3.97 | 5.08 | 34.2 | 10.9 |
Jay Cutler | 234 | 2.73 | 2.6 | 3.64 | 4.57 | 39 | 9.8 |
Sam Bradford | 234 | 2.72 | 2.65 | 3.33 | 4.16 | 37.6 | 14.8 |
Joe Flacco | 217 | 2.71 | 2.58 | 4.37 | 4.25 | 40.1 | 16.1 |
Matt Schaub | 225 | 2.7 | 2.65 | 3.46 | 4.4 | 43.1 | 12.4 |
Tony Romo | 203 | 2.7 | 2.57 | 4.18 | 4.53 | 27.9 | 22.8 |
Drew Brees | 218 | 2.68 | 2.57 | 3.72 | 4.4 | 29.2 | 20.3 |
Matt Ryan | 228 | 2.54 | 2.49 | 3.67 | 3.7 | 41.7 | 9.5 |
Tom Brady | 206 | 2.53 | 2.46 | 3.77 | 4.2 | 31.9 | 16.7 |
Andy Dalton | 195 | 2.51 | 2.31 | 3.97 | 4.64 | 24.6 | 22.9 |
Ryan Tannehill | 208 | 2.48 | 2.28 | 3.6 | 4.3 | 33.8 | 33.8 |
Carson Palmer | 193 | 2.47 | 2.39 | 3.46 | 5.1 | 38.9 | 16 |
Philip Rivers | 201 | 2.41 | 2.32 | 3.49 | 6.2 | 26.9 | 14.8 |
Peyton Manning | 203 | 2.32 | 2.29 | 3.42 | 18.7 | 13.2 | |
Matthew Stafford | 207 | 2.3 | 2.23 | 3.1 | 5.1 | 27.5 | 14 |
MEAN | 211.78 | 2.64 | 2.51 | 3.76 | 4.65 | 33.88 | 16.87 |
STANDARD DEVIATION | 17.34 | 0.23 | 0.18 | 0.39 | 0.60 | 7.05 | 5.93 |
TANNEHILL Z-SCORE | 0.22 | 0.71 | 1.30 | 0.42 | 0.58 | 0.01 | -2.85 |
CORR PRESS % | 0.40 | 0.56 | 0.67 | 0.22 | -0.34 | ||
CORR SACK % | -0.31 | 0.09 | -0.13 | 0.31 | 0.02 | -0.19 |
In the third row from the bottom, entitled “Tannehill Z-score,” what we have is a standardized measure of how far above or below the league average Ryan Tannehill’s statistics are in these areas.
There are only two significant statistics to be found for Ryan Tannehill in that regard in my opinion:
1) The amount of time he’s had to attempt to throw the ball, which is 1.3 standard deviations below the league average, and which means he’s had significantly less time than the average QB to attempt to throw the ball (although that amount of time is just less than a quarter of a second [0.23 seconds], which is about as fast as the blink of an eye), and;
2) The percentage of pressured dropbacks resulting in sacks, which is 2.85 standard deviations above the league average, and which means he’s been sacked significantly more on pressured dropbacks than the average QB, and very much so. That difference is much more than just “the blink of an eye.”
However, contrary to what we might have previously believed, Ryan Tannehill is not being pressured on a greater percentage of his dropbacks than the average QB. He is also not being sacked more quickly than the average QB, and he is not taking any longer than the average QB to throw the ball or to scramble downfield (when he does).
It might seem sensible to close the book on the issue at this point and conclude that Tannehill’s greater percentage of sacks on pressured dropbacks is due to the smaller amount of time he’s had to attempt to throw the ball. It certainly isn’t due to the fact that he’s being pressured more often on dropbacks than the average QB, because he is not.
However, when we correlate 1) the time QBs have had to attempt to throw, with 2) the percentage of pressured dropbacks resulting in sacks (see the bottom row of the table), we find the correlation is -0.13, which means there is little or no relationship between the two variables.
In other words, QBs in the NFL are not being sacked more often because they have less time to attempt to throw the ball. Those two variables are unrelated, and therefore one cannot possibly cause the other. There’s a time-honored statistical maxim most people know that says correlation doesn’t equal causation, but it’s also the case that causation can’t happen without correlation. One variable cannot cause another if it isn’t correlated with it.
Additionally, when we correlate 1) the time QBs have had to attempt to throw, with 2) the percentage of total dropbacks resulting in pressures (see the row of the table above the bottom one), we find the correlation is 0.67, meaning that, contrary to what we might have expected, the more time a QB has to attempt to throw the ball, the greater percentage of the time he’s pressured on his dropbacks. So it can’t be said that Ryan Tannehill is being pressured because he has less time to attempt to throw the ball, when that isn’t the case for quarterbacks across the league.
What we also find by correlating some of the data is that, although the number of total dropbacks has a moderately strong correlation (0.40) with percentage of dropbacks in which QBs are pressured, total dropbacks is negatively correlated (-0.31) with the percentage of sacks in which the QB is pressured. This is an important distinction, because although it suggests that teams that run the ball less (i.e., those with more dropbacks) may be pressured somewhat more, it also suggests they are not sacked more. In fact they are sacked less.
(For any extreme stat geeks out there, please note that I also generated scatterplots for the above variables and investigated the possibility of quadratic relationships, of which there were none. The scatter appeared to be random in all cases.)
The take-home messages are the following three points in my opinion:
1) It’s inconsistent with the above data to believe that Ryan Tannehill’s greater percentage of sacks on pressured dropbacks is due to his having less time than the average QB to attempt to throw the ball.
2) It’s inconsistent with the above data to believe that Ryan Tannehill is being sacked more on pressured dropbacks because the team isn’t running the ball enough.
3) There must be another explanation for Ryan Tannehill’s much higher percentage than the league average of pressured dropbacks that result in sacks.
One possible explanation that’s consistent with the above data is that the amount and/or quickness with which Tannehill moves in response to pressure has been insufficient. This would explain why he’s pressured no more than, and no more quickly than, the average QB, but is sacked far more often than the average QB.
In other words, he may be doing a fine job of getting rid of the ball quickly when he does throw the ball, but a poor job of moving out of harm’s way when he doesn’t throw the ball.
This explanation fits very well with the above data in my opinion, in that Ryan Tannehill has had less time than the average QB to attempt to throw the ball, but more time than the average QB to actually throw the ball. In other words, when he senses pressure, he often gets rid of the ball quickly when he does throw the ball.
However, when Ryan Tannehill is pressured and he does not throw the ball, he’s much more likely than other pressured QBs to be sacked, thus illustrating the “lack of movement” hypothesis alluded to above. Obviously if he’s chosen (for whatever reason) not to throw the ball under pressure, the only other option available to him to avoid a sack is to move. What fits best with the above data is the idea that such movement under pressure on his part isn’t happening anywhere near sufficiently.
And of course this may be something he’s being coached to do, as well: to hang in the pocket and continue to visually scan downfield, despite whatever may be happening with regard to the pass rush.
