While browsing Football Outsiders, I came across their 2007 Drive Statistics.
Here's how the Broncos stack up:
Yards Per Drive: 31.69 (9th best)
Points Per Drive: 1.73 (17th best)
Touchdowns Per Drive: .180 (18th best)
Punts Per Drive: .337 (5th best)
Now let's figure out what these statistics tell us.
Yards Per Drive compared to Points Per Drive and Touchdowns Per Drive
Of the teams in the top 10 in YPD the Broncos have by far the largest difference in their YPD to PPD ranking. Only two other teams in the top 10 in YPD are not in the top 10 in PPD. However, two teams are ranked 11th and 12th, a far cry from Denver's 17th.
The rest of the teams in the top 10 in YPD also have TDPD rankings similar to their YPD rankings. Again, the Broncos exhibit a discrepancy that the rest of the top 10 do not.
Relevance of Punts Per Drive:
If the Broncos were not scoring points, you would expect the offense to be punting the ball quite regularly. Yet that is clearly not the case, the Broncos punted the ball less than the vast majority of the NFL.
The thought might cross your mind now that the Broncos must have been turning the ball over frequently as an explanation for this. But, the Broncos turned the ball over at a decidedly average rate (15th) compared to the rest of the NFL.
What's this mean?
All of this lends to the conclusion that the Broncos were kicking too many field goals and not converting their chances into touchdowns.
That is a recurring theme for Shanahan's Post-Elway Broncos, in 2004 the team was 28th in Red Zone efficiency. The 2006 team was 12th, and the 2005 team despite having the second best record in the NFL was seventh in Red Zone Efficiency. Despite the fact that the Broncos were in the AFC Championship game in 2005, it should be no surprise that they finished behind both Super Bowl representatives in Red Zone Efficiency.
I would be willing to bet that once 2007's Red Zone Efficiency ratings are released, the Broncos will be amongst the NFL's worst.
The consistent problem is the play calling once the Broncos get into striking distance of the end-zone. It is consistently terrible, and Shanahan, as the person calling the plays, is to blame.