Does Home Field Advantage Really Evaporate in October?

When it comes to throwing shade in the playoffs in recent years, nothing has caught as much – not even your least favorite broadcaster – than the concept of home field advantage. The reason for the negative feelings isn’t surprising. Other than a possible first-round bye, home field advantage is the main reward for playoff teams that win more regular-season games than other playoff teams.

It’s true that home teams have struggled in recent postseasons, but they actually haven’t been too bad this year. The 19-18 record of home teams isn’t the most scintillating of tallies, but their .513 winning percentage across 37 games is not exactly a stunning departure from the .522 winning percentage for home teams during the 2024 regular season. The most games a team can possibly play in a single postseason is 22, and nine points of winning percentage works out to only 0.2 wins per 22 games.

Naturally, the data are noisy given the relatively small number of postseason games, even under the current format, but the recent issues with home field advantage seem to mostly be a 2023 thing, when home teams went 15-26, comfortably their worst year. Smoothing out the data a bit doesn’t really do much, either.

You can always find an oddity if you shave data paper-thin like prosciutto, but with data as volatile as this, you’ll mostly end up with bleeps and bloops that don’t really mean anything. Like, sure, teams are 29-31 since 1995 at home in Game 7s and Game 5s, but that’s primarily the odd blip of NLDS home teams going 4-12 in their rubber matches.

Returning to 2023 one more time, I went back and looked at the projections, both from ZiPS and regular-season record or Pythagorean record. Using each team’s actual 2023 record, the average home team in the playoffs had a .562 regular-season winning percentage; it was .551 for the road teams. It’s a .564/.553 split using the Pythagorean records. But I still have all the projected matchups and rosters at the start of the playoffs saved, so I re-projected the results of every actual game that was played. ZiPS thought on a game-by-game basis, with home field advantage completely removed from the equation, the road teams were actually slightly stronger, projecting the average home team at .545 and the average road team at .556. Facing off against each other, ZiPS expected home teams to have a .489 record in the 31 actual playoff games, with an 8% chance of going 15-26 or worse.

Looking at the Wild Card era as a whole, home teams have gone .540 over 1,045 playoffs games. In the regular season over the same era, home teams have a .537 winning percentage. In other words, the playoffs just aren’t that different from the regular season. (ZiPS assumes a .535 playoff winning percentage for the home team in a game of exactly equal teams.) So why does it feel so bad? I suspect one reason can be found in the charts above. Home teams had a pretty good run in the mid-2010s, on the heels of the expansion from eight to 10 playoff teams, peaking at a .581 winning percentage from 2013 to 2017. In that context, it conveys the feeling that home field advantage is working as intended, and the five-year runs stayed slightly above the historical trend until the 2023 home field crash.

Since that crash feels especially bad, it’s natural that people search for deeper meaning in data that don’t really have a lot to give. One common cry was blaming the long layoffs from the bye round. This argument doesn’t hold up, as Ben Clemens pointed out last postseason.

It also doesn’t have much to do with modern baseball or modern players, either. Home field advantage has been relatively stable in the regular season throughout baseball history.

There’s been some long-term decline, but nothing earth-shattering.

The larger problem is simply that fundamentally, home field advantage just isn’t a big deal in baseball. It’s not as big a deal in other sports as some think, but unlike in the other major sports, the difference in baseball between a great team, a good team, a lousy team, and the Chicago White Sox is not that large. Other sports don’t need home field advantage to be as much of a differentiator, especially in the playoffs. A few years back, Michael Lopez, Greg Matthews, and Ben Baumer crunched some numbers and estimated that to match the better-team-advances rate of the NBA playoffs, MLB teams would need to play best-of-75 playoff series. I certainly love me some baseball, but I can’t imagine I’d still watch World Series Game 63 with the same intensity as I do every Fall Classic game now. Besides, the MLBPA wouldn’t be on board, and the calendar would make that a practical impossibility anyway.

Even giving the team with more wins home field advantage in every single game doesn’t drastically weight the dice. Assuming a .535 home winning percentage and evenly matched teams, the home team would require a best-of-13 series to become a 60/40 favorite; to increase its odds to 2-to-1, we’d have to make it a best-of-39 series. Just to experiment, I simulated series with the normal postseason distribution of home field advantage (one extra game) between two teams, the one in which the home team is .020 wins better than its opponent (just over three wins in a season). I then ran the numbers for how often the better team would be expected to win, based on series length.

So what does this all mean? In all likelihood, home field advantage in the playoffs hasn’t changed in any meaningful way. And isn’t really all that big of a deal in the first place. Without altering the very nature of the postseason significantly — aggressive changes such as requiring the lower-seeded team sweep in the Wild Card series to advance — baseball has a very limited ability to reward individual playoff teams based on their regular-season results. Home field advantage isn’t broken; it’s working in the extremely limited way that one should expect. If the Dodgers beat the Yankees in the World Series this year, it probably won’t be because they were rewarded one more possible home game.