“Diversity & Inclusion” is highly topical. In particular gender diversity (still) attracts astonishingly much attention, although at least within white-collar occupations it assumedly has become reality long since. This impression is deceptive: Compared to Scandinavia or Switzerland, the labor force participation of women in Germany is rather low (Oschmiansky, Kühl, & Obermeier, 2014) and even optimistic projections expect the labor force participation rate of women not to reach 90% of the level of men until 2040 (Börsch-Supan & Wilke, 2009). In contrast to the U.S. for example, where the labor force participation rate of women in all likelihood already reached its maximum (Toossi, 2010), there is still room left for the labor force participation of women in Germany to increase, so that gender diversity is still legitimately on the agenda of companies. While bio-demographic diversity is generally discussed from a normative angle, in some companies, gender diversity may be viewed from a functional perspective, too.

Regarding the functionality of diversity, there is a divergence of (scholarly) opinion. The evidence based on meta-analyses, which systematically aggregate the results from all relevant studies, tentatively suggests that gender diversity within teams does not exert any influence on team performance (Webber & Donahue, 2001; Horwitz & Horwitz, 2007; Joshi & Roh, 2009; Schneid et al., 2014). A notable exception is the meta-analysis by Bell et al. (2011), which evidences a negative association between gender diversity and team performance. A meta-analysis by van Dijk, van Engen und van Knippenberg (2012), however, shows that a negative association between gender diversity and team performance is restricted to studies which measured team performance subjectively (instead of objectively), clearly pointing towards rater bias.

A recently published meta-analyses by Schneid, Isidor, Li, and Kabst (2015) now opens up a new and exciting perspective within diversity research: The authors show that the association between gender diversity and team performance is contingent upon national culture!

Only within two groups of societies, Schneid and colleagues detect a significant (negative) association between gender diversity and team performance: First, in societies with strong gender-role differences and little promotion of gender equality such as Egypt and India („gender egalitarianism“; House et al., 2004: 12). In contrast, societies in which the equality between men and women is promoted and differences between male and female role models (also with respect to occupation) are minor, no association between gender diversity and team performance is to be found. Either negative and positive effects of gender diversity balance each other or gender diversity is simply irrelevant to team work and ultimately team performance, because men and women equally participate in the tasks and communication of the team.

Second, Schneid and colleagues find a significant negative association between gender diversity and team performance in collectivistic societies such as Argentina and South Korea. In collectivistic societies, collective action and distribution of resources is institutionally rewarded and promoted. In addition, individuals feel strongly connected to the collectives (for example, organizations or teams) they are part of (“institutional collectivism” and “in-group collectivism”; House et al., 2004: 30). The finding of a negative association between gender diversity and team performance in collectivistic societies is surprising. Contrary to expectations, rather than by means of belonging to a team, a collectivistic orientation welds together by means of belonging to a collective (men/ women) within a team. Hence, especially in collectivistic cultures, tensions and conflicts may emerge in gender-diverse teams and reduce team performance.

A study by Baer et al. (2014) even points towards the concept of gender diversity being misdirected: Baer et al. find gender-specific reactions to competitive situations to impact the creativity of teams, suggesting that the separating line does not run between homogeneous and heterogeneous teams, but rather between homogeneous male and homogeneous female teams. Taken together, the evidence is that, as so often is the case, the general rule regarding the influence of gender diversity on team performance is: It depends!