the national institute of justice has released a new research in brief on the chicago neighborhoods project of rob sampson and colleagues. at one time, nij did much more of this sort of thing, releasing extraordinarily useful "ribs" that summarized grantees' research.
in this report, i find the immigration results most intriguing:
Less violence was committed by youth living in neighborhoods with more first-generation immigrants and where more residents were employed in professional and managerial occupations. Youth living in neighborhoods where adult residents were more cynical about the law also reported more violence. Once these factors were accounted for, the neighborhoods’ racial composition did not matter. - p. 7.