According to this report by The National Council on Crime and Delinquency (NCCD), 23 percent of U.S. students report the presence of gangs at their schools and approximately 35 percent of law enforcement agencies indicate gang problems in their jurisdictions.
The report analyzes data from national, state and local youth surveys and draws on the results of previous gang research. It includes a summary of risk factors for gang membership and selected characteristics of gang-involved youth. California, which has faced significant and disproportionate levels of gang membership for decades, serves as a state case study.