The Phillies have the best home-field advantage in baseball. Here’s the real secret to it.

The Phillies don’t have a home-field advantage at Citizens Bank Park. By now, it’s fair to say that they have home-field dominance at Citizens Bank Park, at least in the postseason. They are 24-11 there, a winning percentage of .686, the highest of any team that has played 20 postseason games or more in its home ballpark.

If anything can hearten them in the wake of their excruciating 5-4 loss Monday to the Braves in Game 2 of the National League Division Series in Atlanta, it’s this: What they have at Citizens Bank Park is way beyond advantage. What they have, most of the time, is home-field physical-mental-intellectual-emotional-aerial-aquatic-territorial-technical superiority.

“There are home-field advantages,” ESPN analyst David Cone said, “and then there’s Philadelphia.”

But why? Why are the Phillies so much better in their own park than the remaining 29 major-league teams are in theirs? It might seem an obvious question to ask and an easy one to answer. The fans, dummy. They’re so loud, and they’re so passionate. This is the best sports town in America, and the Phillies just feed off that energy. All our teams do.

Correct, kind of. Philadelphia sports fans are of course loud and passionate, whether they’re rooting for the Phillies or the Eagles or the 76ers or the Flyers. But none of those other three franchises has been as good at home in the playoffs as the Phillies have. Not over recent history, anyway.

During the Joel Embiid era, the Sixers have won 62% of their postseason games at the Wells Fargo Center, going 18-11. Those 11 losses, though, include Games 5 and 7 in 2021 against an inferior Atlanta Hawks club, Game 6 to the Miami Heat in 2022, and Games 3 and 6 against the Boston Celtics this year. The Eagles have won eight of their 12 playoff games at Lincoln Financial Field, but even with that smaller sample size, they still can’t match the Phillies’ home winning percentage. As for the Flyers, it has been more than five years since they last hosted a playoff game (no, the 2020 tournament in the pandemic bubble doesn’t count), and they’ve lost 13 of their last 21 postseason games at the Center.

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So what’s really at work here? A few factors. To assemble and arrange these factors into an operating theory of Phillies Home-Field Supremacy, I spoke Monday with Dr. Ronald Kamm, a sports psychiatrist and formerly an associate professor in Drexel University’s School of Medicine. Those are important credentials. So are these: He’s a Mount Airy native and a huge Philadelphia sports fan.

All anyone had to do to understand this truth was spend five minutes watching any of last week’s American and National League wild-card games. Compared to the Phillies’ two victories over the Miami Marlins, each of those series felt and sounded as if it were being played in a library. The Tampa Bay Rays failed to draw 20,000 people to Tropicana Field. The Minnesota Twins couldn’t fill Target Field, and the Milwaukee Brewers couldn’t fill Miller Park.

The thing is, those more sedate environments were closer to what ballplayers experience throughout a 162-game regular season. In contrast, Citizens Bank Park throbs from the first pitch to the last, which makes it a shock to the system of any opponent who isn’t accustomed to it.

“The atmosphere there is like no other,” Kamm said. “Normally, an opposing player will be focused on the players in front of him, maybe the players in the dugout. But really, the way the fans are the Bank, opposing players have to focus on what’s around them. There’s a natural feeling, in a playoff atmosphere particularly, of being surrounded.”

Two words: Trea Turner. Now, 280 words to reaffirm the point:

During our conversation, Kamm described a demonstration he witnessed at a sports psychiatry lecture. Before an audience of 75 people, the presenter had a volunteer, a woman who had been an elite athlete, leave the room. While she was gone, the presenter instructed the audience members to think “horrendously negative thoughts” about her once she returned. So they did.

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After a few minutes of speaking to the volunteer on stage, the lecturer stopped the conversation and said, I want to try an experiment. He stretched his arms forward until they were as straight as ramrods, and he asked the volunteer, the ex-athlete, to try to push his arms down.

“She couldn’t,” Kamm said. “As strong as she was — she was bigger than him, stronger than him — she could not get his arms to budge much.”

Then the lecturer repeated the entire sequence, with one big difference. This time, when the volunteer re-entered the room, the audience was to think “incredibly positive thoughts about her.” And this time, when the lecturer extended his arms, “it was like she was pushing on a feather,” Kamm said.

“I don’t think I’ve ever been as struck by a demonstration,” he continued. “She didn’t really know why she didn’t feel strong the first time. She just felt weakened. The second time, she felt so energized. So the lecturer said, ‘You just saw a demonstration of the home-field advantage.’

“Forget what Phillies fans do verbally and with their body language and their banners and their totems and all that. Forget all that. Just the negative thoughts they’re sending to Brian Snitker and Matt Olson and Ronald Acuña — it has an effect.”

This factor is mostly intuitive, of course, but it makes sense. Playing baseball is generally a much more deliberative exercise than playing football, basketball, or hockey. Take the last of those. It doesn’t seem a coincidence that since 2008, home teams have won just 55% of all NHL playoff games. There’s a common mantra among the sport’s coaches when their teams play on the road: Simplify. Don’t be fancy and daring. Be basic and safe. Hockey is all instinct and reaction. Get back to that. Don’t overthink.

Now, consider the time that any baseball player has during a game to live in his own head. A batter is thinking while he’s in the on-deck circle and in the box. A pitcher is thinking while he’s on the mound. A fielder is thinking while he’s manning his position. And if you’re a visiting player in South Philadelphia, you’re doing all this thinking in front of a crowd that is very much a living, seething, bellowing thing.

No doubt, there have been times when the reverse has been true, too: The anxiety that Phillies fans have felt over the game’s outcome can seem oppressive, such as in the team’s 1-0 loss to the St. Louis Cardinals in Game 5 of the 2011 NLDS.

But on the whole, Citizens Bank Park tests an opposing player’s mental strength, especially an opposing pitcher’s, to a degree no other ballpark does. Remember CC Sabathia vs. Brett Myers and Shane Victorino in the 2008 NLDS? Remember Jonathan Broxton grooving a bottom-of-the-ninth fastball to Jimmy Rollins in the 2009 NLCS? It’s a challenge, amid those conditions, to be precise with your pitches, and the job is made all the more difficult for the emotional buoyancy that the Phillies players receive from the fans’ support.

“In Philly, you’re playing in front of family,” Kamm said. But if you’re the opponent, “you’re taking on a team. You’re taking on a fan base. You’re taking on a city. You’re taking on a region. It’s very tough for an opposing team. And anytime you divide an athlete’s focus, you’re impairing their performance.”

After what happened Monday night, the Phillies need all the impairing they can get.