Is There an Advantage to Playing Games at Home vs Away in the MLS?

This report uses data from the 2020 season of the MLS to investigate if there is evidence of a home advantage. Analysis suggests a home advantage is present, across teams and possible reasons and reccomendations are then suggested.

This graph shows away win rates compared to home win rates for each team. From this graph we can see that home win rates are generally higher for most teams. Average win rate across teams at home was 0.52 and away was 0.27.

This bar chart shows the goal difference (goals scored - goals conceded) for each team, home and away. At home goal difference was higher for most teams (average across all teams 0.64 ) than away (average -0.64 across all teams) meaning more goals tend to be scored and less conceded when playing at home.

This box plot shows the variability of team performance both at home and away, based on goal difference. Goal difference tends to be positive at home and negative away again suggesting more goals are scored and less conceded at home.

Summary & Evidence Based Recommendations:

From the data analysis it can be concluded that there is a home advantage in the MLS, calculated as 62.3% meaning 62.3% of points come from home games. This is on par with home advantage in different leagues - UEFA Nations League 2018-19 had a 60.6% home advantage.

There is a significant difference in home vs away win rate, goals scored and goals conceded. Estimated mean result per away game is -0.579 less than home games, which when looked at in context of 17 away games played per team per season = a loss of 9.8 points, from the data we have also found an average goal difference of -1.08 per away game and 0.543 less goals are scored at away games.

Most common reasons for a home advantage include impact of travel, crowd effects, referee bias, players familiarity with their home ground and tactical decisions. Travel distance accounted for 0.412% of variance in match outcomes in this data, meaning it did not have a significant impact on match score directly, however further analysis could look into travel distance impact on other metrics such as high speed running or total sprints per match which may affect match score. Interestingly the team with the lowest home advantage - D.C. United 37.5%, accumulated the highest travel distance over the season with 77500km traveled.

From past research, it has been sugested up to 79% of away wins occur in the MLS when the away team get better quality shots, which equates to a higher goal conversion rate. Away game team tactics are usually more defensive which decreases offensive opportunities and the chances for good quality shots making goals less likely.

It is suggested home / away games have the biggest impact psychologically on the athlete and coach, with higher levels of self confidence and testosterone when playing at home, coaches should therefore reconsider the importance of location when deciding on tactics and instead focus on building team confidence with away games.

To attempt to counteract the loss of familiarity when playing away it could be useful for teams to familiarise themselves with the away stadiums before the game, although not always possible, if prioritized could help minimise any negative away effect.

The findings from this data are consistent with previous studies, that a home advantage exists within the MLS however home advantage is a complex and multi-factorial issue and the size of the home advantage at team level requires further analysis alongside other data such as league position of the teams which will help to establish individual team, home advantage effect.