It's not the theory of relativity, but it was complicated to me!
Everyone rates a team's defensive performance differently. Some think that it's all about total yards allowed, some believe that stopping the run is most important and others think it's all about points allowed.
The reality is all three are important.
I decided to use a combination of math and judgment to determine each teams' defensive power ranking for the upcoming season.
1. I took 2010 team rankings in the following defensive categories: Pass yards allowed, Rush yards allowed, Total Yards allowed, and finally, Points allowed. I added a 50% weight to points allowed, because I believe what shows on the scoreboard is where games are won and lost.
2. I took all those rankings and averaged them to give each team a modified overall rank.
3. I then asked myself, "did this team help or hurt themselves or remain static in the off season?" I converted the answer into a scale of one through five. 1=Dramatic Regression, 2=Moderate Regression, 3=Little to no change, 4=Moderate Improvement, 5=Dramatic Improvement. I called this the "Improvement Modifier."
4. Each improvement modifier was given a value. If a team showed dramatic regression, their overall rank would be multiplied by 1.20. This would increase the number, thereby putting them lower on the list. These modifiers decrease by 0.1 until they reach 0.8 for a team that improved greatly, thus lowering their number and subsequently moving them higher on the list.
The final number after all these calculations is the "final modified ranking" and determined the list you've just read.
The only subjective aspect of this list is what number was assigned to the "improvement modifier." For that, I looked at coaching and talent upgrades, loss of talent/coaches and draft class. Unfortunately, due to the lockout, free agent signings played no part in these rankings.
Example: Hypothetical team "X" is ranked 10th in every category. Therefore, their points against is modified to 5 and this is averaged with the rankings of the other categories to give them a modified overall rank of 8.75. That number is multiplied by their "Improvement modifier" of 5 (.8) for their improvement in the off season, to give them a final modified ranking of 7.
Keep in mind that no team had a final modified rank better than 2.475 or worse than 28.6. The average rank for all 32 teams was 15.916, (due to ties is several categories)
Boy, I hope that made sense!