Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
When social pressure leads to favoritism, policies might aim to reduce the bias by affecting its source. This paper shows that multiple sources may be present and telling them apart is important. We build a novel and granular dataset on European football games and revisit the view that supporting crowds make referees help the host team. We find this bias to remain unchanged even in stadiums closed due to Covid‐19. Instead, influential host organizations emerge as the source of social pressure. This has an adverse effect on maintaining the ranking of influential teams and hindering the progress of smaller teams.