Diversità nei team e performance: il ruolo moderatore delle credenze e delle norme di gruppo

Diversity research has yielded ambiguous results concerning the effects of diversity on work group processes and performance. The Categorization Elaboration Model (CEM, van Knippenberg, De Dreu, Homan, 2004) accounts for this inconsistency in results and points out two different underlying processes that have independent and interactive effects: elaboration of task relevant information and social categorization. Diversity has positive effects on performance to the extent that it engenders elaboration brought about by a great variety of resources and perspectives. At the same time, diversity may be detrimental to performance to the extent that it engenders social categorization and intergroup biases that may disrupt information elaboration processes. Several authors (Homan, van Knippenberg, van Kleef, De Dreu, 2007a) advanced the theoretical notion that norms, beliefs and attitudes valuing diversity are needed to harvest the potential of diversity. Group openness to diversity is defined as the extent to which the group views value encourage and support diversity (Hartel, Fujimoto, 1999; Homan, Bordia, Gallois, 2004). Group diversity beliefs are defined as beliefs about the value of work group diversity to work group functioning (pro-homogeneity vs. pro-heterogeneity; van Knippenberg, Haslam, 2003; Homan et al., 2007a). So far, however, few quantitative tests on the relationship of group openness to diversity and of diversity beliefs with team performance (e.g., innovation) and team processes have been conducted in the field. In the present field has been tested the moderating role of group openness to diversity and of team diversity beliefs on the relationship between nationality, age, gender diversity, as well as faultline (Lau, Murnighan, 1998; 2005), formed by age and gender diversity and team innovation. A total of 59 teams and 59 leaders filled out the questionnaire (N= 441, 382 members and 59 leaders). The leader rated innovation and performance. Data has been analyzed at the group level, following James, Demaree, Wolf’s (1984) recommendations for Rwg(j). As suggested in Preacher and Hayes (2007; 2008) we tested for elaboration as moderated mediatior, and for multiple mediation of elaboration, using bootstrapping re sampling. A moderating role for group openness to diversity was confirmed both in the relationship between team nationality diversity and team innovation, and on the relationship between team age diversity and team innovation. The moderating role of group openness to diversity norms is confirmed in the relationship between gender diversity and team performance. Concerning the moderating role of group diversity beliefs, this was verified in the relationship between team nationality and team innovation as well as in the relationship between faultline (made by gender and age diversity) and team performance. The multiple mediation (Preacher, Hayes, 2008) and moderated mediation (Preacher, Hayes, 2007) tested with bootstrapping resampling method did not yeld any statistically significant results, with the exception of gender diversity. Further possible developments on multilevel analysis using Euclidean distance as dissimilarity at the individual level are finally discussed. To conclude, it’s confirmed that group openness to diversity norms mitigate the negative effect of nationality diversity and age diversity on team innovation; furthermore, openness to diversity norms mitigate the negative effect of gender on team performance. Moreover, group pro-heterogeneity beliefs lessen the negative effect of nationality diversity on team innovation, and lessen the negative effect of diversity faultline on team performance. The present results are discussed both in terms of their theoretical and practical relevance.