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 vs. 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” and a few highlights include:

• This week’s ESPN “Monday Night Football” matchup featuring the No. 2 and No. 5 defenses. The Patriots, at No. 5, are held back by their third-down performance.

• The Ravens are on the rise, from No. 6 last week to No. 4 this week, as they are in position to make another post-Thanksgiving run.

• The Falcons defense dropping from 31 to 32, as the Jaguars bump up one spot.

• The Cardinals’ strong defense shouldn’t be overlooked.

• It’s somewhat surprising to see the Browns ranked so low as the defense is widely viewed as a team strength.