Youth violence is a serious global public health problem. Despite a decline in homicide rates across the United States during the 1990s, homicide rates are again rising and continue to claim the lives of many young people. The human and economic toll of violence on young people, their families, and society is high. Homicide is the second leading cause of death for persons 15-24 years of age and has been the leading cause of death for African-Americans in this age group for over a decade. The economic cost associated with violence-related illness, disability, and premature death is estimated to be in the billions of dollars each year. This compendium provides researchers and prevention specialists with a set of tools to assess violence-related beliefs, behaviors, and influences, as well as to evaluate programs to prevent youth violence. Readers who are new to the field of youth violence prevention and unfamiliar with available measures may find this compendium to be particularly useful. For experienced researchers, this compendium may serve as a resource to identify additional measures to assess the factors associated with violence among youths. An index is included. [Report published by the National Center for Injury Prevention and Control.]