Information from the National Survey on Gang Migration and other literature provides a look at the relationship between gang migration and proliferation. "Gang migration" refers to the movement of gang members from one city to another. Whether such movement has played a major role in the proliferation has been the focus of several studies, including the National Survey on Gang Migration conducted in 1992. Law enforcement personnel in approximately 1,100 cities answered questions about the movement of local gang members, and telephone interviews were conducted with law enforcement officers in 211 cities that reported the arrival of at least 10 migrant gang members in 1991. Findings from these studies and other data provide evidence that gang member migration, although widespread, should not be viewed as the major culprit in the nationwide proliferation of gangs. Law enforcement officers usually do not see migrants as the cause of gang problems. Cities with gang problems should examine the dynamics of their own communities before attributing their gang problems to outside influences. (Contains 3 figures, 2 tables, and 33 references.) (SLD)