Diversity as a booster: the role of squad diversity and cohesion in association football

This paper investigates the joint impact of squad diversity and team cohesion on performance outcomes in professional football, using data from 155 Premier League squads across eight seasons. While prior research has often examined diversity and cohesion separately, this study assesses their combined effect on team success. Drawing on a large-scale dataset of over 40,000 players—including demographic information, performance metrics, and career history—we construct indices for cohesion and three dimensions of diversity: age, nationality, and club history. Team cohesion is measured by average shared playing time, while diversity is based on differences in age, nationality, and previous clubs. Regression analysis confirms that cohesion positively predicts team performance, measured by total points earned in a season as well as table position. Among the diversity measures, we identify an interaction effect: nationality diversity amplifies the positive influence of cohesion. This suggests that cohesive squads can perform better when underpinned by nationality diversity, challenging assumptions that diversity inherently hampers coordination. This research supports a shift from viewing diversity solely as a moral imperative to recognising its strategic value, providing new insights into the conditions under which diversity becomes a performance booster.