The Importance of Home Field Advantage

2020 continues to be a baffling year from all angles of life. Sports, of course, are no different as the MLB put together an odd 60 game season with an expanded playoff format, no fans, and lots of new rules.

As we enter the second round of the playoffs, being played at neutral sites, I took a second to think about the impact of home field advantage.

Astros fans are very familiar with the advantages that Minute Maid Park can give. With unique dimensions, a retractable roof, and lively screaming fans, players know when they’re in Minute Maid Park. We’ve also faced some rulings that left a bad taste in the mouths of fans - such as a “home game” being played against the Cubs at Miller Park, or rulings to leave roof open.

But how much difference does home field advantage actually make? And what actually drives it. Is it players designed to take advantage of specific dimensions? Is it fans booing or cheering to drive you on? Or familiarity, knowing how to play hits to different parts of the park?

MLB.com did an article highlighting that home field advantage had completely evaporated this year. Here were a few snippets from their article:

Home team winning percentage, MLB

Since 1901 (Birth of the AL): .541

Since 1920 (Live Ball Era): .541

Since 1947 (Integration): .538

Since 1969 (Divisional play): .538

Since 1998 (30-team era): .536

Since 2008 (Pitch-tracking era): .538

At the time of writing, the MLB was at .505. Immediately supporting the notion that not having fans in the stands limited, if not eliminated, home field advantage.

They go in to analyze the strike zone, which Fangraphs had previously found to be the largest factor in Home Field Advantage. And there’s a logical basis, as referees in other sports are often found to lean towards the home field, particularly with tens of thousands of screaming fans. This year, for the first time, road teams have actually received a benefit on strike/ball calls.

But as the rest of the season played out, the results regressed back to normal, and actually showed a return to the expected win percentage for the home team, actually all the way back up to a .557 winning percentage. (the highest since 2010)

MLB’s article touched on it, but the belief on the primary difference was the differential in travel, given the way this season was designed to minimize it. Here were a few of the quotes from the Fangraphs article:

“We found that athletes, when traveling, on average got an hour less sleep than athletes that did not travel,” Ahmed said. “An hour less in bed, 45 minutes less sleep. That’s about 10% lower recovery. Conventional wisdom says the home team wins because they have their fans supporting them or they are playing in a familiar park. The study suggests the home team may win because they are better recovered and better well rested.”

“There was a direct correlation between the higher your recovery and the faster your exit [batted ball] velocity. We found the same correlation with pitchers and fastballs,” Ahmed said. “I didn’t know for sure we were going to see such strong correlations with travel, recovery and performance. Those were a bit of a eureka [moment] with us and for people in Major League Baseball who saw this study.”

But with limited travel this year, research isn’t supporting this theory in 2020’s results. Additionally, research by Baseball Prospectus found that the elements of success are more likely to be linked to familiarity with the park than benefits of home cooking. Their research showed the declines in home field advantages to new parks, and did an in-depth analysis of the advantage of playing the in-town rivals to eliminate the advantages of not having to travel, and staying at home rather than in a hotel.

In fact, Baseball Prospectus dug extremely deep into the topic, with a series of 5 articles. [1] [2] [3] [4] [5], which covered a wide array of topics digging into the differential on first vs last game played at a visiting stadium, age of players, advantages on different elements of the game, differentials based on distance/travel, etc. With all that said, there was no definitive but more of a culmination of elements that caused it.

On the opposite side, there’s been arguments made in regards to how much of an impact home field advantage has ever made. While historic trends show a significant advantage, The New York Times is quick to cite that all 7 games last year were won by the away team. And while a single series is never a sample size to make decision on, their analysis, particularly on wild card winners, did not show the home field advantage would expect, since the single game elimination games have entered the conversation.

But all of the research and topics above were related to playing within your home stadium with the modified rules and lack of fans. The playoffs? Well, we’re going to be entering something completely different.

Screaming fans? Gone. Advantage to strike zone? Gone. Advantage to knowing the field? Gone. Building your team to maximize advantages of the dimensions? Gone.

All of this results in the only real advantage of “home field” is that you have the last chance to bat. And while that’s still something, it’s definitely not the same.

There’s an argument to be made that the Astros will be entering “hostile territory”, but without fans in the stands, I can’t imagine it having any major differential impact. There were notes that players familiarity with a stadium did play a factor, so the Astros having a history in Los Angeles may actually lend some aspects of an advantage to them.

Nonetheless, like everything else in 2020, it’ll be interesting to watch it play out. I’m hopeful the Astros are able to recapture some of that magic as the underdogs and take everyone by surprise.

Admittedly, the desire for the first World Series ever played at Mimic Maid Park in Arlington, Texas to have an Astros logo painted on their field increases my desire for the Astros to make it a hundred times over. There’s no place like home. Except when there is.