he topic is home-field advantage, but on second thought, maybe Matt Birk isn't the best guy for this job. This past December, the Baltimore Ravens center and his wife Adrianna welcomed their sixth child, Brady, into the world.
"Home-field advantage?" Birk said recently, laughing. "Not anymore."
The raw numbers over the past decade suggest the Ravens are the happiest at home among the NFL's 32 teams. So why doesn't M&T Bank Stadium turn up on those ubiquitous lists of the league's toughest venues?
"That's a question for your colleagues in the media," said Birk, who graduated from Harvard with a degree in economics. "No. 1, I'm going to say that over the years the Ravens have fielded a pretty good football team. No. 2, the fans here are great.
"It's pretty simple. There's your home-field advantage."
Ah, home sweet home ... where the heart is ... a state of mind. That metaphorical place to which you can never, ever, truly return.
In the hurly-burly world of the NFL, however, it is a concrete concept -- as starkly real as a Jason Pierre-Paul sack.
Over the past decade, only one team -- the New York Giants -- has managed to produce a better winning percentage on the road than at home. The Saints (45-37 on the road and 46-37 at home over that time) have come tantalizingly close. The fact that those two teams have won three of the past five Super Bowls underlines the importance of succeeding in the face of that home-field advantage.
In the last two games played in Week 3, the home teams prevailed in wildly controversial finishes, but bottom line, the Seahawks and Ravens found ways to beat the Packers and Patriots. Oh, and how about those Vikings over the 49ers in the raucous atmosphere of the building now known as Mall of America Field at Hubert H. Humphrey Metrodome? Playing at home in Week 5, the scrappy Kansas City Chiefs managed to stay within a field goal of the Ravens.
Why do teams fare better at home? It's a comfortable, familiar environment; for road teams, of course, it's just the opposite. The local weather patterns and quirks of the stadium are a known quantity. The fans are ferocious. No matter how long the journey, road teams have to expend time and energy to get there.
"Emotion manifests itself in football as much or more than any other sport," said Scott Pioli, the Chiefs' general manager, from his office at Arrowhead Stadium. "The energy from the surroundings is incredible. This game is such a human sport, so emotional, that an arena can actually help generate that energy."
Denver cornerback Champ Bailey is in his 14th NFL season. Recently, he checked in by cellphone after lifting weights, listing Philadelphia, Oakland and Atlanta as his three least-favorite places to play.
"Philly is unbelievable," Bailey said. "Their fan base is as raw as they come. Oakland, the team hasn't been great but the fans talk a lot of trash. Atlanta, it can get really loud in that dome."
None of those venues made ESPN.com's short list of toughest places to play.
"Really?" Bailey asked.
And then, as each of those daunting stadiums was mentioned, Bailey would groan as suppressed memories came flooding back.
"Man, those are tough places to play," he said. "I guess I just tried to put those out of my mind."
Every fan likes to think his team is toughest at home, but how do you quantify that?
Last spring, ESPN.com's intrepid NFL bloggers offered a top-10 power ranking that placed Green Bay's Lambeau Field first, followed by Pittsburgh's Heinz Field and Seattle's CenturyLink Field. Denver's Sports Authority Field at Mile High and Baltimore's M&T Bank Stadium did not make their cut.
Needless to say, this isn't an exact science.
The simplest method is to look at home-field victories. Since 1990, the Packers and Steelers have won more home games (129) than anyone. But, it's worth noting, they have also been among the league's best teams over that time. How do you get past that?
One way is to examine a team's home winning percentage versus that on the road. The Patriots, for example, have the league's best winning percentage at home over the past decade, .829 (68-14). But they are also a tidy .699 (58-25) on the road. That means Gillette Stadium provides New England with a differential of only plus-.130, a number that puts the Patriots in the lower half of the league.
The Ravens, on the other hand, have a home winning percentage of .771 since 2002, compared to .415 on the road. The difference (.356) is the league's greatest. The Arizona Cardinals, believe it or not, have the second-best differential. But 10 years is a relatively small sample. Going back 20 years, the Packers have the greatest home-road differential (excluding the Ravens, who are in their 17th season in Baltimore). Take it back to 30 years and it's the Chiefs at Arrowhead.
ESPN.com queried more than two dozen folks in and around the NFL -- players, owners, general managers past and present, scouts, analysts and writers -- in an attempt to identify the league's toughest venues. The lesson learned: It's a highly emotional and, therefore, subjective business.
Ask Bill Polian, the former general manager of the Colts, Panthers and Bills, the most difficult place his teams had to play.
"New Orleans, by far," said Polian, now an ESPN analyst. "That place was always incredibly loud."
This was a popular opinion, but over the past three decades the Saints have the league's lowest home-road differential playing in what is now named the Mercedes-Benz Superdome.
Tedy Bruschi played linebacker for the Patriots for 13 seasons and, like Polian, is now an ESPN analyst. After all the numbers have been crunched, after the local atmospherics have been accounted for, Bruschi agrees with Birk that team strength and fans are the two leading factors. And each pushes the other to a higher, better place.
"The fans know they have a good team," Bruschi said. "When you get that combination, that's what makes it hard when you're on the road. They're more motivated to be really loud."
Buildings, however crafted to support their teams (or vice versa), are only mortar and metal. Ultimately, it's about the people. The toughest venues all feature extremely invested fans, which, we remind you, is short for fanatics. The communities that back their teams the best have an almost psychological dependency on them; maybe that's why Los Angeles -- which has struggled to support the NFL over the years -- doesn't have a team. The Chiefs, for example, draw fans from six states. The Packers are the only game in Green Bay, Wis.
The Ravens, meantime, are making separation anxiety work for them.
When Birk arrived in Baltimore in 2009 after 11 seasons in Minnesota, the first thing that struck him was the passion of the fans. Baltimore lost the Colts to Indianapolis after the 1983 season and went a dozen years before the original Cleveland Browns franchise relocated to Baltimore. Since the Ravens arrived, they have 91 home wins; only two teams, the Patriots and Packers, have more.
"This city lost its football team," Birk said. "The Ravens filled the void for them, and the fans are really into it here. That makes for a loud stadium on Sundays."
And that makes for a significant home-field advantage. Here, listed in order, are the Sweet Six-Pack -- or, if you are a visiting team, the Dirty Half-Dozen. All things considered, these are our choices as the league's toughest places to play. It's probably just a coincidence that none of them have roofs.