How is Defensive Pass Efficiency calculated?

I've looked everywhere but cannot find out the formula to calculate this rating.

I read that it involves the following:
1. Passing yards allowed per game
2. Passing Completion Percentage
3. Int total
4. Percentage of Ints thrown
5. TD Total
6. TD Rate
7. Yards passing per attempt
8. Yards per completion avg

The NCAA formula for Offensive Passing Efficiency is:
[ {(8.4 * yards)+(330 * touchdowns)-(200 * interceptions)+(100 * completions)}/attempts ].

I'm very curious to know what the formula is for defensive eff. Anyone know?