Data Analysis on True Value of Home Field Advantage in the Playoff

by Tyler Young

From 2003 until 2017, Major League Baseball tried something different. Rather than giving home field advantage in the World Series to the team that won more games during the regular season, it was determined based on the outcome of each season’s All-Star Game. Just about everyone around the league hated this system, and it was eventually scrapped. But why the vitriol? Does it really make a difference where the games are played?

 

Prior to last season’s baseball playoffs, a study by The Action Network revealed that the home team in an MLB playoff game came out on top 54 percent of the time, which was the exact same rate that the home team won games in the regular season. The 2017 postseason exacerbated this advantage, as home teams won 27 out of 38 competitions, or 71.1 percent, including both wild card games and all seven matchups in a tight ALCS between the Astros and Yankees.

 Photo Credit:  thatlostdog--  on  Visual Hunt  /  CC by

Photo Credit: thatlostdog-- on Visual Hunt / CC by

Since 1969, the year that MLB added the Championship Series round, the host club has won 55.6 percent of all playoff games. That margin increases with each round. In the wild card games, which have only existed since 2012, the home team wins just 41.7 percent of games. That goes up to 52.4 percent in the Division Series, 55.7 percent in the Championship Series and a massive 60.1 percent in the World Series.

 

For what it’s worth, the team with home field advantage in the World Series has won six of the last 10 championships, but it has been the “road” team to come out on top in the two most recent Fall Classics.

 

Let’s look at this year’s crop of contenders. Going into the final week of the 2018 regular season, there are only 11 teams with a shot at one of the 10 available playoff spots. All five AL positions have been claimed, as have three in the NL. Of the 11 teams with meaningful games to play, six perform better at home than they do on the road, but all 11 have winning records both away and in the friendly confines.

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Clearly, there is some significance to “home field advantage.” Such a consistent track record tells us that much. Even still, the correlation is fairly weak. In a vacuum, the outcome of a baseball game is a coin flip. Adding in a specific setting doesn’t approach guaranteeing a win for the host team, but it does move the needle, ever so slightly, in their favor. And in the postseason, those slight edges can make a massive difference.