Sunday, January 25, 2009

Strong Defense Slightly Better Than Strong Offenses In 2008

Teams with much better defenses did better than teams with much better offenses in the 2008 NFL regular season, but only by a little more than you'd expect from the usual home field advantage so it might not be much of an advantage.

In Super Bowl XLIII, the Pittsburgh Steelers have a much better defense but the Arizona Cardinals have a much better offense. How did this combination of factors play out in the 2008 regular season?

Let's use the number of points scored and given up as a rough measure of how good a team's offense and defense is. It is not certainly not perfect for a variety of reasons (no adjustment of strength of schedule or garbage time scoring), but it is a simple objective measure for our analysis.

Next, let's look at agmes where one team had a stronger offense (better than one point per game) and the other team had a stronger defense (better than one point per game).

When home teams had a stronger offense but weaker defense, they went 22-18, just slightly worse than the average for home teams. When visiting teams had a stronger offense but weaker defense, they went 14-22, slightly worse than the average for visiting teams. This suggests the team with the better defense does slightly better, so a slight advantage to the Steelers.

If we look at teams that had a much stronger offense (better than 5 points per game advantage) but a weaker defense (worse than 5 points per game advantage), we see that this only happened for visiting teams with strong offenses and weaker defenses. It happened 5 times and the visiting team went 2-3, slightly worse than the average for visiting teams, but too small of a sample size to make much of a conclusion.

This analysis doesn't take into account how the Steelers have an advantage with its defense (13.5 points per game) that is much bigger than the Cardinals have a better offense (5.3 points per game).


Anonymous RJ_Bell said...

Rex -

Just stumpled on you. Great insight.

I have an idea for us.

Here's my site:

I recieved a lot of press on the Tim Donaghy scandal.

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1:58 PM  

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