As I watched the horror that was the San Jose State game, I was shaken out of my despair by an odd comment from the announcers. They mentioned that it was surprising BYU's offense was struggling as BYU is such an offensively-oriented team. Anyone who has watched BYU play anyone other than Hawaii or Idaho would not call BYU an offensively-oriented team. That was point #213 in why Joey Galloway is a terrible color-commentary guy (point #1 was "Cody Nelson"), but it hammered home the theme of this season: BYU's offense is terrible.
The question is why is the offense so bad. There are generally two schools of thought - either it's Riley's fault or it's Doman's fault. In an attempt to be objective about this, I've resorted to math. Aside from standard metrics like passer rating (PR), total offense (YPG), and offensive points per game (PPG), I’ll also be using Football Outsider’s S&P+ defensive rankings for BYU’s opponents. For a full description of S&P+ see the FO website, but basically S&P+ measures a team’s defensive effectiveness while adjusting for the quality and tempo of the opponent. Using a teams' S&P+ ratings allows us to compute expected statistics - what an "average QB" or an "average offense" should do against the defenses BYU faced over the past two seasons. You can think of this as similar to the "wins above replacement" statistics used in baseball, where a player’s performance is compared with what a statistically average player would have done.
For each of the 21 games against FBS opponents in the past two seasons I've computed the expected PR, YPG, and PPG and then compared BYU's actual performance against those expected values. If Doman is the problem we would expect to see all averages of three categories come out negative, indicating the offense has been worse than a statistically average one against the defenses BYU has faced. If Nelson is the problem we might expect to see a stronger negative average in PR than in YPG or PPG. And of course we're also interested in trends rather than simply looking at individual games or averages. A downward trend over time would be particularly troubling because it would indicate that either Doman's coaching is not improving his players' or that Nelson is regressing as a QB.
Here's how BYU's offense has done in the past two years relative to expectations in these three categories:
As you can see, the numbers are not good. While the offense has had some good games, the average over the last two years is ugly. BYU's offense has been 6% worse than average in PR, 2% worse than average in YPG, and 6% worse than average in PPG. The most interesting things, however, are the trends. While PR hasn't gotten any better, both YPG and PPG have.
Statistically, the numbers indicate that while everything about the offense is bad, the only part that is not improving is the play of Riley Nelson. Hopefully, that means that once Riley graduates and becomes BYU's grittiest alum, the improvements Doman has made to the rest of the offense will finally extend to the QB position.