This publication summarizes findings and evidence from Federal reviews of research studies and program evaluations to help localities address childhood exposure to violence and to improve outcomes for children, families, and communities. In reviewing the research literature on evidence-based programs, common characteristics have emerged in the findings that have been shown to either support success or reduce the effectiveness of programs. This paper highlights two types of service characteristics. The first lists facilitators' characteristics that are common across a range of programs that are associated with better outcomes. The second lists barriers, or those characteristics that can prevent programs from being successful. A third list includes common service and system gaps documented as practical implications discussed in the research literature. Data were collected from the following databases prepared by the Office of Juvenile Justice and Delinquency Prevention (OJJDP) and the Substance Abuse and Mental Health Services Administration (SAMHSA): SAMHSAs National Registry of Evidence-Based Programs and Practices, SAMHSAs National Child Traumatic Stress Network, OJJDPs Model Programs Guide, and OJJDPs Children Exposed to Violence Evidence-Based Guide.