Tedy Bruschi's defensive index

When judging total defense in the NFL, many often point to yards allowed as the primary measure for a unit’s effectiveness. ESPN analyst Tedy Bruschi sees that as a flawed analysis.

Bruschi instead has put together his own formula, averaging what he views as the four key statistics: points allowed (only on defense, not including pick-sixes or special-teams scores), red zone defense (measured by percentage of touchdowns allowed versus total trips), third-down percentage and total turnovers (created solely by the defense, not including special teams).

What results, with an assist from Jason Vida of ESPN’s Stats & Information department, is the “Bruschi defensive index.” A few highlights of this week’s index include:

• The Panthers taking over the top spot from the Chiefs.

• The Ravens’ strong performance in the red area and third down keep them in the top 5.

• Credit to the Jaguars for playing hard and moving up one spot for the second straight week.

• The Patriots continue to struggle on third down, but their takeaways are a big plus.

• The Saints’ No. 9 ranking highlights how they are a more balanced team this year, not just relying on offense.