Bayesian analysis of home advantage in North American professional sports before and during COVID-19 One aspect of familiar surroundings that should not be overlooked is the familiarity with the playing surface. Different stadiums and fields can have varying characteristics, such as the type of grass, dimensions, or even weather conditions. Teams that are accustomed to playing on a specific surface can adapt their playing style accordingly, while visiting teams may struggle to adjust. That is, both teams have a home advantage but this advantage is significantly greater for the team that plays at home second. The relationship between crowd effects and referee decisions operates through multiple mechanisms. Comparing the effect of crowd noise on different size venues may go some way to rectify this limitation, though of course it again limits internal validity by removing randomization and control over conditions. The home advantage disappears completely in midweek games, which can be considered an unfair advantage for teams with fewer home games during midweek. This discrepancy can be further impacted by imbalanced schedules where teams do not face the same opponents as each other in a perfectly balanced manner. Rugby data further supports this pattern; analyses show that home teams boast higher win rates, often by margins of 10-15% compared to away teams. The physical nature of rugby, combined with vocal home supporters, plays a crucial role here. Coaches frequently cite these home advantage statistics to inform tactics and psychological preparation. For instance, in the Premier League, the unpredictability of teams and match outcomes can make betting tricky. We may add that sport officials may not just wish to conform just because of feeling valued by a partisan crowd, but arguably also because they feel intimidated by such a crowd. While both forms of conformity may be at play, we argue that normative conformity can only really be influential in experimental participants’ decisions, where a live crowd is present and they perceive their decisions will be evaluated by others. Pettersson-Lidbom and Priks found referees’ adjusted their decisions to appease home supporters, punishing away players more harshly and treating home players more leniently. Interestingly, Van de Van found no difference in home advantage across the same series of games. This suggests that a crowd may influence officials’ behavior but may be unnecessary for home advantage to occur. Enhancing external validity and representative design These inclusions are beyond the scope of this work as these analytics and personnel changes and their effect differ greatly across different sports. In future work, we hope to focus on an individual sport and include such factors, using the current model as a baseline to compare against. Our model is also limited by focusing on only point totals to infer home advantage, while some previous works also analyze differences in penalties to assess a home advantage in the officiating of games5,7,8,10. This was excluded from this work because of how much penalties and their effect differ across the various sports we considered, but is something we hope to explore in the future when analyzing a single sport in more depth. Win Rates Finding a balance between objectivity and subjectivity in refereeing decisions is a challenging task. One potential solution that has been proposed is the introduction of video assistant referees (VAR). VAR allows for crucial decisions to roobetofficial.com be reviewed and corrected based on video evidence, reducing the potential for bias. However, the implementation of VAR has also faced criticism, with concerns raised about its impact on the flow and spontaneity of the game. Another option is to have neutral referees officiating matches, removing any potential influence from the home crowd. Ultimately, the best strategy may depend on the team’s ability to cope with external distractions and maintain composure under pressure. The historical data surrounding home advantage in the league provides valuable insights into its impact on team performance. From statistical analysis to psychological and tactical perspectives, it is clear that playing at home can provide teams with an edge. However, it is crucial to recognize that home advantage is not a guaranteed path to victory. Additionally, measures can be taken to ensure unbiased officiating and fair treatment of both home and away teams. Away teams often have to travel long distances to reach the home grounds of their opponents. This travel can lead to fatigue and disruption in their normal routine, affecting their physical and mental preparation for the game. Jet lag, different time zones, and unfamiliar sleeping arrangements can all impact the performance of away teams. In contrast, home teams have the advantage of being able to rest and prepare in their own familiar environment. Conformity is considered to be the result of either normative or informational influence (Deutsch and Gerard, 1955). As such, individuals conform either to be more accurate, for affiliation or to maintain positive self-concept (Cialdini and Goldstein, 2004). Cialdini and Goldstein (2004) argued that when accuracy is the motive for conformity, it is because the conformer believes others have cues for successful behavior. In the case of sports officials and crowd noise, this relates to the official considering the vocalized opinions of the majority of fans offering useful additional information to guide their decision. Conversely, normative conformity results from the conformer wanting to be accepted or valued by the group and demonstrating their agreement with the group or sport fans’ views.