The Case AGAINST Prevent Defense

[Brian Carter]

After watching our 1st half fall apart, I figured some thought and analysis on "prevent" defense was warranted.  Most of us probably felt this is the case, but nice to know when they line up like this, we aren't crazy for feeling anxious:
 

The "prevent" defense is a widely debated strategy in football, particularly in late-game or end-of-half situations where the primary goal is to prevent big plays rather than aggressively stop shorter gains. While it has its uses, statistics and analysis often criticize it for several reasons:

1. Yards Allowed Increase

• Statistics: Teams utilizing the prevent defense tend to allow more yards per play compared to their standard defensive formations. NFL and college football data show that prevent schemes can allow an increase of 20-30% more yards per play than base defenses.
• Analysis: By playing softer coverage and rushing fewer defenders, offenses exploit underneath routes and intermediate gains to move down the field quickly.

2. Scoring Efficiency by Opponents

• Statistics: Opposing offenses have a higher scoring efficiency when facing prevent defenses. Studies have indicated that teams score on around 50-60% of drives when prevent defenses are used, compared to a lower percentage against traditional schemes.
• Analysis: The cushion provided allows quarterbacks to make easier completions, often leading to field goal range or late-game touchdowns.

3. Time of Possession Impact

• Statistics: Despite limiting deep plays, prevent defenses often fail to consume enough time, as teams can complete quick sideline passes and preserve clock while advancing the ball.
• Analysis: A team in a two-minute drill can effectively move 40-50 yards in just 30 seconds without much resistance, as the defense focuses on deeper coverage rather than contesting short routes.

4. Conversion Rates

• Statistics: Third and fourth-down conversion rates significantly increase against prevent defenses, with some studies suggesting conversion rates over 70%, as compared to 40-50% against standard defensive looks.
• Analysis: The softer zones give offenses manageable distances to convert, leading to sustained drives and scoring opportunities.

5. Win Probability Models

• Statistics: Advanced analytics and win probability models show that teams switching to prevent defenses in close games see a 4-10% decrease in win probability, depending on the time remaining and field position.
• Analysis: Prevent defenses often lead to complacency, allowing opponents to gain momentum and pressure the defense in critical moments.

6. Red Zone Effectiveness

• Statistics: Once an offense enters the red zone against a prevent defense, scoring percentages rise to over 75%, due to the reduced field space negating the deep-zone advantage.
• Analysis: The prevent defense fails to adjust efficiently to red-zone spacing, making it easier for offenses to exploit matchups.

[syracusehorn]

Case for prevent defense: 75 yard Screen pass against tOSU  for a TD with :22 seconds left in the first half.

 

I think there's a balance where you play base defense with no blitzes or overloads, but no extra cushions or dropbacks either. 

[yoyocc]

We didn't run prevent on the screen pass.

[hookemrj13]

14 minutes ago, yoyocc said:

We didn't run prevent on the screen pass.

we ran "eh its halftime, they gonna take a knee"

[NBHorn64]

26 minutes ago, yoyocc said:

We didn't run prevent on the screen pass.

He was making a case for using the prevent defense. We decided to blitz and they killed us.