Stats: Compelling but not indicative

Numbers, of course, can lie. Still, certain truths can be found in the long columns of digits the NFL produces each season.

In the interest of public service, we offer the following number, courtesy of Steve Hirdt, executive vice president of the Elias Sports Bureau: 6.

In the 25 years since the bye was instituted in the NFL playoffs, only six teams that played in the first round advanced to the Super Bowl. That means New England, Kansas City, Philadelphia and St. Louis -- who are all sitting at home with an extra week off -- are the heavy favorites to reach Super Bowl XXXVIII in Houston.

So, NFL fanatics, watch those tasty little playoff games this weekend but understand that, statistically speaking, the Titans, Ravens, Cowboys, Panthers, Seahawks, Packers, Broncos and Colts may well be playing irrelevant games.

Sorry to do that to you, but sometimes the numbers can be cruel.

On the flip side, three of those teams playing in wild-card games -- the 2000 Baltimore Ravens, 1997 Denver Broncos and 1980 Oakland Raiders -- won four postseason games, including the ultimate contest. So, as with every number, take it with the proverbial grain of salt.

Hirdt, who also crunches numbers as the Director of Information for ABC's Monday Night Football, is a wise man. He qualifies his numbers with patience and precision. Earlier this week, when asked to make some definitive judgments about turnovers, Hirdt was not quite buying it.

"You have to be a little bit careful," Hirdt said. "Not to be Clintonesque, but I think turnovers are a great predictor in retrospect … ."

As evidence, he cited Super Bowl XVIII, played 20 years ago in Tampa. The Washington Redskins had amassed an amazing plus-43 turnover net in going 14-2 during the regular season. The Raiders had a huge minus. The result, however, was a 38-9 Raiders victory -- and the critical play was a turnover. The Redskins were trailing 14-3 with seven seconds left in the first half when Raiders linebacker Jack Squirek intercepted Joe Theismann at the 5-yard-line and ran it in for a touchdown.

That said -- in the interests of stimulating a lively water-cooler discussion with some statistical food for thought -- the turnover numbers for playoff teams are instructive. Two of the bye teams -- New England and St. Louis -- lead their respective conferences in takeaways. Coincidence?

"You start with (takeaways/giveaways). That's the No. 1 stat," said Colts President Bill Polian. "Look at the six teams from the AFC and the first five teams are all in the playoffs. Only Denver is minus, and they're a bit of an anomaly because they were without their starting quarterback for four or five games."

In a field-leveled league defined by parity, a turnover is a momentous event. Not only is the team on offense relieved of the ball -- and the chance to score -- but the other team suddenly has that opportunity. The swing in field position alone can make a difference in a tight game.

The Chiefs and Patriots, who happen to have the best two records in football (13-3 and 14-2, respectively) also happen to have the two best turnover nets. Again, we ask, coincidence? Kansas City is at plus-19, thanks to 37 takeaways and a league-low 18 giveaways. The Patriots, thanks to their league-high 29 interceptions, are at plus-17. Carrying the concept further, seven of the top nine turnover nets belong to playoff teams -- as good a correlation between an NFL statistic and bottom-line success that you will find.

The exceptions to the rule -- San Francisco and Minnesota -- are No. 4 and No. 5 at plus-12 and plus-11, respectively. Both teams suffer from problems that mitigate those tidy numbers -- namely, defense.

The 49ers (7-9) had the league's fifth-ranked offense, but the defense was ranked No. 13. The 9-7 Vikings were one of only two teams that had a winning record and failed to make the playoffs. The offense was ranked No. 1, but the defense was 23rd. Minnesota and San Francisco each allowed more points (353 and 337, respectively) than any playoff team.

Irresistible vs. immovable

Which brings us to this age-old debate: Defense, the adage goes, wins championships. But does that still hold true? In recent years, it seems offense has had more of a hand in a team's postseason success. The 1999 Rams scored 540 points, the third-highest total on record, and won Super Bowl XXXIV. Consider that seven playoff teams are ranked among the league's top nine offenses, in terms of yards. The Chiefs, Colts and Packers are Nos. 2-4.

"You would think so," Hirdt said of the apparent offensive trend. "But let me tell you about something that happened last year."

Super Bowl XXXVII was an ABC game, so Hirdt was preparing along with analyst John Madden. The game was a unique case study because, for the first time, it featured the No. 1 offense versus the No. 1 defense. Playing the role of irresistible force was the Raiders, who had scored 450 points in the regular season. The immovable object was the Tampa Bay Buccaneers, who had allowed a paltry 196 points.

The Bucs, who scored 34 unanswered points after falling into an 0-3 hole, won 48-21. Incredibly, the defense played the Raiders even; three interceptions, two by Dwight Smith and one by Derrick Brooks, were returned for touchdowns.

"There were nine previous Super Bowl games where a top-three offense played a top-three defense," Hirdt explained. "The defensive-oriented teams won eight of those games. But since most of those were back in the 1980s, John and I were wondering if that might have changed.

"Well, now the number is 9-for-10, for the defense. That was eye-opening for me."

Now, before you go running for those stats, here are the 12 playoff teams, ranked by yards allowed per game: 1. Dallas (253.5), 2. Baltimore (271.3), 3. Denver (277.1), 4. New England (291.6), 5. Carolina (295.3), 6. Indianapolis (299.3), 7. Tennessee (306.3), 8. St. Louis (315.8), 9. Green Bay (318.8), 10. Seattle (327.4), 11. Philadelphia (331.7), 12. Kansas City (356.7).

The first three teams on the list all had serious issues on offense, particularly in the passing game. This, according to those who know, puts them at serious risk in the playoffs.

"Defense is essential, but in the playoffs you have to have some offense," Polian said from his office in Indianapolis. "The exception would be New England or Buffalo, where weather can be such a determinant.

"In the regular season, you can get by without it. You get the running game going and play good defense and you might be OK. But in the playoffs, you've got to be able to score points."

Inexperience under center

The first weekend's playoff games will be heavily populated by unproven postseason passers. On Saturday, it's Anthony Wright vs. Steve McNair in the first game and Quincy Carter vs. Jake Delhomme in the second. McNair (4-3) is the only one of the four to have started a postseason game. On Sunday, Matt Hasselbeck, a playoff newcomer, faces Brett Favre, whose playoff record is 10-7. The late game features Peyton Manning and Jake Plummer, who have one playoff victory between them -- and that, believe it or not, belongs to Plummer.

Just another reason to like the four teams waiting with byes.

Of course, two years ago the Patriots started a guy named Tom Brady, who had never played in the playoffs. He went 3-for-3 and won the Super Bowl XXXVI MVP. Just another example of working the numbers in two different directions.

Polian has two favorite bottom-line offensive stats: yards per pass play and average per rush. Here are the top five in each category:

Yards per pass play: 1. Tennessee (7.76), 2. Kansas City (7.43), 3. Indianapolis (7.34), 4. Seattle (6.94) and 5. Green Bay (6.85).

Average per rush: 1. Green Bay (5.0), T2. Baltimore, Philadelphia and Denver (4.8), 5. Seattle (4.4).

Interestingly, New England, the favorite of many experts based on its 12-game winning streak, is not on either list. In fact, the Patriots have the fifth-worst yards-per-pass number (6.39) and the second-worst average-per-carry figure (3.4). What to make of that? Those numbers are probably more a product of the cautious nature of head coach Bill Belichick and staff. Once New England gets a lead, it likes to grind the ball on the ground. When the need to pass arises, Brady can fling it -- as the Buffalo Bills, 31-0 losers in the regular-season finale, will tell you.

Seven of the 12 teams that reached the postseason achieved 11 victories or more, an impressive number. This is a playoff field that ESPN.com colleague Len Pasquarelli has correctly concluded is "one of the deepest and most dangerous in recent history." And while the Patriots won more games (14) than any other team, their offensive statistics -- unlike linebackers Tedy Bruschi and Willie McGinest -- are not knocking people over.

Consider the margin-of-victory statistic:
The Chiefs (9.5) are far and away the NFL's best in this respect, followed by the Packers (8.44), Rams (7.44) and Titans and Colts (6.94). New England, at 6.88, is tied with the Ravens for No. 6 on the list.

The Patriots' calling card, however, is defense.

In the bottom-line area of points allowed, New England (238) led the league, followed by Dallas (260) and Miami (261). This is worth mentioning, because twice in the last three years the Super Bowl winner was the team that allowed the fewest points in the regular season. The Bucs (196) did it last year and the Ravens (165) turned the trick in 2000. Going back, the 1996 Packers (210) managed it as well, so it has happened three times in seven seasons.

And that, in the final analysis, is as good a number as any.

Greg Garber is a senior staff writer for ESPN.com