Home-audience advantage in basketball: evidence from a natural experiment in Euro League games during the 2019-2021 Covid-19 era

Abstract

Introduction: Τhe possible audience effect on basketball game-related statistics in a natural setting has not been itself investigated. The EuroLeague Basketball, began the 2020-21 season with restrictions on audience attendance at the games, depending on national and/or local health guidelines, due to the Covid-19 pandemic. Αs a consequence, these extreme conditions provided the rare opportunity to explore the possible effect of homeaudience advantage (HAA) on the most important basketball game-related statistical indexes of team technical performance (Team Performance Indicators – [TPIs]) during the last two regular seasons (2019-21) with an audience and with no audience in a natural setting. Material and Methods: The TPIs (e.g., Points, Rebounds, Fouls) derived from the same 17 teams and 112 games that took place in each season based on predefined inclusion-exclusion criteria and provided by EuroLeague’s official site. Home advantage (HA) of the included teams was calculated as the number of home wins expressed in a percentage (%) of the total number of games included for analysis in each season (i.e., N=112). It was assumed that, except of the possible audience effect, the interaction of various factors which could impair HA would be equal in both seasons and all teams; thus, HAA per se would be reflected in the difference of home advantage between the two seasons. Results: The home teams won significantly more games with an audience (69) in comparison to away teams (43), whereas with no audience they did not. In the season 2019-20 the HA was 61.60%, 4.46% of which corresponds to HAA. Most TPIs were not affected by the presence or absence of an audience and were not different between home and away teams. However, home teams with an audience committed significantly (p<0.05) fewer Turnovers (11.92±1.95) in comparison to home teams without an audience (13.33±1.26). Discussion: Our findings confirmed, not only the existence of the HAA, but also the significant interaction of HAA on HA phenomenon and revealed that audience support was a necessary precondition for the HA when the away team was not equally familiar with the stadium as the home team in EuroLeague’s regular season. This knowledge of the teams’ performance may help teams’ personnel, psychologists, and coaches to develop proper game strategies, training and mental practices which may further improve the teams’ technical performance. Conclusions: Findings supported the notion that HAA has a strong effect on winning frequency and on reducing Turnovers of home teams.