Home Sweet Home: The MLB Teams with the Greatest Home Field Advantage
PLUS: Examining the most hitter-friendly ballparks.
While the home team in baseball has the natural advantage of getting to bat last - and hence the opportunity for a walk-off win - there is more to gain by playing in your home park. From the support of your hometown fans, to sleeping in your own bed, to the lack of jetlag from traveling across the country, there are a multitude of benefits of a game on your diamond. League-wide, dating back to the start of the 2021 season, home teams win approximately 53% of the time (a winning percentage of .531, to be exact). Some teams, however, find more success in their home park than others. By finding the difference in winning percentage between games played at home versus on the road, we can identify which clubs own the greatest home field advantage. The table below ranks MLB teams based their winning percentage at home minus their winning percentage on the road for games dating back to the start of the 2021 season. The right-most column indicates if a team’s record at home is significantly different then their record on the road at the 95% confidence level.1
Every team, with the exception of the Washington Nationals and Houston Astros, wins more at home than on the road. The Colorado Rockies have, by a large margin, the greatest home field advantage. The Rockies situation is unique in that their park, Coors Field, sits at 5,190 feet above sea level - nearly 5-times higher than the next highest park, Chase Field in Arizona.2 It could be that the Rockies have simply learned how to play in the conditions of high altitude and related factors, and structure their team to their environment. Coors Field has been widely considered throughout baseball as one of, and arguably THE, most hitter-friendly stadium in the league. Its reputation has even given rise to what is called the “Coors Field effect”, which attempts to summarize the effects of the atmospheric conditions of the stadium on batted ball distance and scoring. However, further investigation shows that while balls may fly further at Coors Field, home runs there are not as common as many think.
Homer-Friendly Fields
The table below ranks stadiums based on their home run rates, as measured by home runs per plate appearance. The “Extra Distance” column represents the Statcast metric measuring how much further an identically hit ball - based on launch angle and exit velocity - would travel at that park compared to the average based upon temperature, elevation, presence of a roof, and other environmental factors.3
While we would expect to see balls travel 18.6 feet further at Coors Field, the park ranks just 15th in overall home run rate. Interestingly, distance added has virtually zero effect on home run rate. In fact, there is a mere -0.04 correlation between HR% and Extra Distance. A correlation this low can and should be interpreted as having no effect, and the negative relationship is quite likely due simply to random noise. You can see this lack of relationship in the visualization below.
We see here that a park’s “extra distance” factor does not independently make it a hitter’s ballpark. So how can we determine the true most offensive-friendly fields?
Hitter-Friendly Ballparks
I examined the Statcast park effects for wOBA (Weighted On-Base Average), runs, and home runs, which represent the relative frequency of each stat compared to the other parks. The league average is set to 100, so for example the 114 value for runs for Fenway Park means that 14% more runs are scored at Fenway compared to other ballparks. Similarly, the 96 for runs for Yankee Stadium translates to 4% less runs scored there compared to the others. These numbers control for batter and pitcher handedness and represent a 3-year rolling average. To determine the most hitter-friendly ballparks, I took the geometric mean of the three stats to attain an overall offensive average.4 Below are the results.
While the extra distance on balls hit at Coors Field may not produce quite as many home runs as we may expect, it still narrowly comes out as the most hitter-friendly ballpark, edging-out Great American in Cincinnati. It seems as though a multitude of factors contribute to the hitter-friendliness of fields. While there may be some truth behind the “Coors Field effect”, there are certainly many factors at play that determine whether a ballpark is more pitcher or hitter friendly.
Conclusion
Baseball stadiums are unique. Each is located in a different geographic area and unlike football, basketball, soccer, and really any other sport, the dimensions - aside from the basepaths - all differ. When you play half your games in one park, you need to construct a team and learn how to play in a way that thrives in that environment. A pitcher-friendly field should, in theory, support a more pitcher-centric squad, and vice-versa. While some teams appear to do so better than others, it is clear that, generally speaking, teams in baseball greatly benefit from playing at home.
Based on a t-test testing average wins at home versus away over that time span. Each team has played essentially the same number of games at home and on the road.
Per Statcast: “The total distance added is broken down into these sub-factors. Temperature (every 10°F adds 1% distance); Elevation (every 800 feet adds 1% distance); Roof (adds 1% distance); and Environment (everything else not otherwise captured, like humidity, wind patterns, etc.”
Geometric mean was used to account for the dependencies and multicollinearities between the three statistics and neutralize the potential for the average being skewed up or down by outlying numbers.