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Violence: School-Based Programs


What the Task Force Found

About The Systematic Review

The Task Force finding is based on evidence from a systematic review of 53 studies (search period through December 2004). The systematic review was conducted on behalf of the Task Force by a team of specialists in systematic review methods, and in research, practice, and policy related to violence prevention.


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Summary of Results

Fifty-three studies met the systematic review inclusion criteria.

  • For all grades combined, the median effect was a 15.0% relative reduction in violent behavior among students who received the program (interquartile interval: -44.1% to -2.3%; 65 study arms).
  • By school level, the median effects on violent behavior were as follows.
    • High school students: median relative reduction of 29.2% (interquartile interval not calculated; 4 study arms)
    • Middle school students: median relative reduction of 7.3% (interquartile interval: -35.2% to 2.3%; 21 study arms)
    • Elementary school students: median relative reduction of 18.0% (interquartile interval: -44.8% to -2.5%; 34 study arms)
    • Pre-kindergarten and kindergarten students: median relative reduction of 32.4% (interquartile interval not calculated; 6 study arms)
  • All intervention strategies (e.g., informational, cognitive/affective, and social skills building) were associated with a reduction in violent behavior.

Summary of Economic Evidence

Most studies identified by our search reported the costs of programs but no economic summary measures based on both costs and benefits.

Reported program costs varied widely:

  • Less than $200 per child for a program implemented in nine schools in the Tucson metropolitan area
  • $2449 per teacher and $98 per child for a program in 15 New York City elementary schools
  • $15-$45 per student per year for a 3-year program, depending on staff turnover.

The only study that estimated both costs and benefits was based on the Seattle Social Development Project, a comprehensive, intensive, and long-term program that focused on elementary schools in a high-crime urban area.

  • The average decrease in basic crime outcomes was 13%.
  • The total benefits, including cost savings to taxpayers because of reduced expenses for the criminal justice system and reduced personal and property losses for crime victims, were estimated to be $14,426 in 2003 U.S. dollars per participant.
  • Net saving per participant amounted to $9837.
  • This program showed a benefit of $3.14 for every dollar invested in the program.

Investment in universal school-based programs to prevent violence has the potential for significant positive economic returns in the future.


Findings should be applicable to students in all school environments, regardless of socioeconomic status or crime rate, and among all school populations, regardless of the predominant ethnicity of students.

Evidence Gaps

Each Community Preventive Services Task Force (Task Force) review identifies critical evidence gaps—areas where information is lacking. Evidence gaps can exist whether or not a recommendation is made. In cases when the Task Force finds insufficient evidence to determine whether an intervention strategy works, evidence gaps encourage researchers and program evaluators to conduct more effectiveness studies. When the Task Force recommends an intervention, evidence gaps highlight missing information that would help users determine if the intervention could meet their particular needs. For example, evidence may be needed to determine where the intervention will work, with which populations, how much it will cost to implement, whether it will provide adequate return on investment, or how users should structure or deliver the intervention to ensure effectiveness. Finally, evidence may be missing for outcomes different from those on which the Task Force recommendation is based.

Identified Evidence Gaps

Some school programs are more effective than others. What characteristics of the programs, or perhaps of the settings in which they are implemented, make some programs or settings more or less effective?

There appears to be a decrease in program effectiveness as time after the completion of the program increases. It will be important to explore ways to extend the benefit of programs, either within the programs themselves or with booster programs.

Are school programs equally effective for high-risk and low-risk children, and in high-risk and low-risk environments? Are programs targeted to high-risk children overall more effective, and, if so, more cost effective, than universal programs?

Many programs assessed in the review were not ongoing, standing programs, but instead were conducted for purposes of research. Because research programs are often more effective than ongoing programs—perhaps because of the intensity of monitoring and implementation—it will be important to understand what maximizes the effectiveness and sustainability of ongoing programs.

In what ways is the effectiveness of universal school-based programs to prevent violence moderated by the predominant ethnicity of the student population? How might addressing cultural and social differences in diverse populations improve the effectiveness of school programs?

Studies of the economic efficiency of school programs, measured, for example, as net benefits or cost-benefit ratio, should assess not only violent or criminal behavior averted, but all current and future social, health, academic, and labor-market outcomes associated with school violence prevention programs. It will be interesting to assess what proportion of the total benefits is crime-related. It will be important to assess the extent to which the data used in the derivation of the summary measure are nationally representative.


Study Characteristics

  • Study sample sizes ranged from 21 to 39,168 students, with a median sample size of 563.
  • Forty-one studies (77.4%) used direct measures of violence or aggression, and 12 studies (23.6%) used proxy outcome measures.
  • Follow-up time ranged from none (assessment immediately following the end of the intervention) to 6 years; the median follow-up time was 6 months.
  • Following are characteristics of the evaluated programs:
    • Programs were offered in pre-kindergarten, kindergarten, elementary, middle school, and high school classrooms.
    • All children in a given grade or school, regardless of prior violence or risk for violent behavior, received the programs.
    • Some programs targeted schools in high-risk areas, including those with low socioeconomic status, high crime rates, or both.
    • Elementary school and middle school programs usually sought to reduce disruptive and antisocial behavior using an approach that focuses on modifying behavior by changing the associated cognitive and affective mechanisms.
    • In middle and high school, the focus of programs shifted to general violence and to specific forms of violence, including bullying and dating violence. The interventions used an approach that made greater use of social skills training and emphasizes the development of behavioral skills rather than changes in cognition, consequential thinking, or affective processes.