Home court advantage has long been observed across professional sports, with basketball showing one of the strongest effects.
COVID-19 created a unique “natural experiment,” with 53.4% of 2020–2021 NBA games played without crowds.
This study aimed to isolate the crowd’s role in home advantage by examining game outcomes, referee decisions, and player performance with vs. without fans.
How does the presence of a home crowd enhance NBA team performance and effort?
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During the COVID-19 pandemic, teams played in a "Bubble" with no actual fans in attendance, while digital boards lined the court with virtual fans as shown in image above.
What Did the Researchers Do?
Study Overview
- Sample: 1,080 NBA regular-season games from 2020–2021.
- Design: Natural experiment comparison between games with fans (N = 503) vs. without fans (N = 577).
- Controlled Variables: Team and opponent strength, travel direction/magnitude, and possession count.
Outcomes Measured
- Winning Percentage, Points Differential, Net Rating
- Foul Differential (referee bias)
- Free Throw %, FG%, 3PT% (distraction)
- Total, Offensive, Defensive Rebounds & Rebound Rate (effort)
What Were the Results?
Home Advantage
Significant difference in performance with crowds present.
- With fans: 58.7% win rate and +2.18 point differential.
- Without fans: 50.6% win rate and –0.13 point differential.
Crowds Increase Effort
- Effort Hypothesis (Rebounding): Crowds increased the total rebound differential (+2.3), especially offensive boards.
- Referee Bias: No significant difference in foul differential.
- Distraction Hypothesis: No impact on FT%, FG%, or eFG%.
Mediation Model
- The increase in rebound differential fully mediated the crowd’s effect on points differential.
What Does This Mean?
- Home crowds don’t appear to sway referees or distract away shooters, but do inspire greater effort in home teams.
- Rebounding efforts are significantly improved in front of fans.
- Effort, rather than referee calls or opponent errors, is the key mediator of home advantage.
Limitations
- Team-level (not player-level) analysis.
- Maximum crowd density was only 46% due to pandemic restrictions, so the effects of full capacity remain unknown.
Coach’s Takeaway
- Rebounding effort drives home advantage; can teams and players build systems to replicate this on the road?
- Focus on motivating "hustle plays" (O-boards, 50/50 balls) in away games.
Reference
Leota, J., Hoffman, D., Mascaro, L., et al. (2022). Home is where the hustle is: the influence of crowds on effort and home advantage in the National Basketball Association. Journal of Sports Sciences.
