Bleacher Report gives a provocative headline to an item from the Green Bay Press–Gazette’s Pete Dougherty:

Does Green Bay Even Need a Defense?

Green Bay not only needs a defense; the Packers have a defense. It is not, however, according to Daugherty, a very good defense, but it wasn’t a very good defense at this time last year either:

The Packers grew into a top defense in 2010 for many reasons, most importantly because several players emerged as key performers as the season went on.

The main question as the Packers hit their bye is whether the same thing will happen this year. It’s also worth asking whether their defense will need to be as good to win another Super Bowl, considering they have possibly the best offense in the league.

As a starting point, it must be noted that for all the yards the Packers have allowed, in important ways their defense is performing about as it did through seven games in 2010. This year’s Packers rank substantially worse in yards allowed (No. 27, to No. 18 last year), passing yards allowed (No. 31 to No. 14) and sacks percentage (No. 17 to No. 6), but they’re better in points allowed (No. 9 to No. 12), red-zone defense (No. 7 to No. 16) and interceptions (No. 4 to No. 6).

The only truly important stat in that paragraph is points, and, again, the Packers are better than they were a year ago. Passing yardage can be misleading because, if a team is behind, it is more likely to pass than run. Teams that are ahead all the time thus will face more passing, particularly of the prevent-defense dink-and-dunk variety.

I figured this out from high school football – specifically the 2003 Ripon Tigers, which gave up 15.2 yards and 258.8 yards per game. That sounds good but not great, but that’s because of their offensive statistics — 45.2 points and 454.9 yards per game — and, by the way, their record, 14–0. More significant than a team’s points per game, either on offense or defense, is the margin (offensive points minus defensive points) per game.

Here is proof from a six- or seven-game sample: The only undefeated team is the Packers, which are also number one in margin — 32.9 offensive points per game, 20.1 defensive points per game, for a difference of 12.8 points per game. The next four in margin per game are Baltimore, which is 4–2; San Francisco, which is 5–1; New Orleans, which is 5–2; and New England, which is 5–1. All of those teams are leading their divisions except for Baltimore, which is a half-game back of Pittsburgh.

Those five teams are all near the top of the NFL in offensive points per game — New Orleans is first, Green Bay second, New England is fourth, San Francisco is fifth and Baltimore is eighth. The defensive points per game rankings are different: Baltimore is first, San Francisco is second, Green Bay is 10th, New England is 15th and New Orleans is 17th.

Less than half a season isn’t a large sample, and this could be one of those statistical measures that reveals itself only at the end of a season, not in the middle. But judging from this half-season, it seems that, in the NFL, offense is indeed more important than defense, and that there is a more of a correlation to a team’s success in margin rather than in offense or defense.

Dougherty adds:

Of the most commonly cited statistics for judging a defense, total yards might be least telling. The one that matters most, aside from points, probably is opponent’s passer rating.

There, the Packers aren’t as good as they were seven games into 2010, when opposing quarterbacks had a rating of only 72.6. But at 79.3 this year, they still rank a notable No. 9 in the league.

“The formula for us right now is, as long as our quarterback continues to play the way he is, and if we can keep our (opponent’s) quarterback rating down into the 70s,” defensive coordinator Dom Capers said this week. “Aaron (Rodgers) right now is (125.7 points). That’s a pretty good differential. So I think that’s a winning formula.”

Just for comparison, Rodgers’ passer rating last year after seven games was 89.0, a 16.4-point differential from opponents, and the Packers were 4-3. This year, with a 46.4-point differential, they’re 7-0. …

For now, though, the Packers are giving up big yards but winning with turnovers and red-zone stops. There’s reason to wonder whether that eventually will bite them against a good team in a big game. Or maybe they’ll just outscore their defensive shortcomings when the games count most.

How important are turnovers and red-zone stops? Say a team gets the ball on its 20 and takes it to the opponent’s 10-yard line, where it then throws an end-zone interception. (Sound familiar, Kyle Orton?) Your defense has given up 70 yards, but more importantly, zero points, while adding one to its turnover margin and decreasing its red-zone scoring percentage.

Games are not decided by yards; they are decided by points, though obviously yards lead to points. We’ll see if the Packers can continue to emulate the 1983 Washington Redskins, which got to their second Super Bowl despite losing to Green Bay 48–47 and having a pass defense that called itself the “Pearl Harbor Crew.”