Here is the abstract for “Who is bullying whom in ethnically diverse primary schools? Exploring links between bullying, ethnicity, and ethnic diversity in Dutch primary schools”, by Jochem Tolsmaa, Ioana van Deurzenb, Tobias H. Starkc, and René Veenstrad, published in Social Networks, Volume 35, Issue 1, January 2013:
This study investigated associations between ethnicity, ethnic diversity, and bullying among 739 pupils enrolled in their last year of primary school. Hypotheses derived from social misfit and inter-ethnic relations theories were tested using the multilevel p2 model. Our key findings were: (1) inter- and intra-ethnic bullying are just as common in ethnically heterogeneous as in homogeneous classes; (2) pupils belonging to the Turkish and Moroccan minority groups bully significantly more than native Dutch (in particular according to victims); the chance to be victimized does not depend on the ethnic background of the pupil; (3) the prevalence of inter- and intra-ethnic bullying depends on the level of ethnic diversity in the class; inter-ethnic and intra-ethnic bullying increase with increasing levels of ethnic diversity.
One can add this to the long and growing body of evidence that, qua Robert Putnam, where there is more diversity, there is an inverse breakdown in social capital.