A case in point is the study by Linda Sax at UCLA, who used data from a large national survey of college freshmen to evaluate the effect of single-sex versus coeducational high schools.
The Sheffield investigation, which involved sixteen primary schools and seven secondary schools, found that most schools succeeded in reducing bullying.
A survey I conducted with Irene Whitney found that in British primary schools up to a quarter of pupils reported experience of bullying, which in about one in ten cases was persistent.
In the archives of the Shanghai International Settlement police Department, there were the police station interrogation records and the arraignment awarded by the Shanghai District Court.