The Effects of School-Based Intervention Programs on Aggressive Behavior: A Meta-Analysis

NICHCY’s Structured Abstract 7 describes the following:

Title | The Effects of School-Based Intervention Programs on Aggressive Behavior: A Meta-Analysis

Authors | Wilson, S.J., Lipsey, M., & Derzon, J.H.

SourceJournal of Consulting & Clinical Psychology, 71(1), 36-49.

Year Published | 2003

Research on the effectiveness of school-based programs for preventing or reducing aggressive behavior was synthesized with a meta-analysis. Changes in aggressive behavior between pretest and posttest were analyzed for developmental patterns and characteristics associated with differential effects. Control groups showed little change in aggressive behavior, but there were significant reductions among intervention groups. Most studies were conducted on demonstration programs; the few studies of routine practice programs showed much smaller effects. Among demonstration programs, positive outcomes were associated with a variety of study, subject, and intervention characteristics. Most notably, higher risk youth showed greater reductions in aggressive behavior, poorly implemented programs produced smaller effects, and different types of programs were generally similar in their effectiveness, other things equal. [Abstract from author.]

There is a need of programs that reduce and prevent behaviors such as fighting, name-calling, bullying, and general intimidation that can create a negative school climate and lead to serious violence. Therefore, the effectiveness of school-based programs for preventing or reducing these forms of aggressive behavior is the focus of this study. School-based intervention programs have been evaluated to support systemic review of their effectiveness and can be cataloged into two categories:

  • demonstration programs, implemented and evaluated by a researcher mainly for research or demonstration purposes; and
  • routine practice programs, in which the program being studied already exist in the school on an ongoing basis and the evaluation is conducted either by school-based or outside researchers.

This meta-analysis* focuses specifically on changes in aggressive behavior and does not take into account changes in attitude, skills, and intention. Studies on any school-based program that measured aggressive behavior as an outcome variable and programs identified explicitly as violence or aggression prevention programs were included.

Research Questions
This meta-analysis had two major purposes:

  1. Differentiate research-oriented demonstration programs from practice-oriented programs and evaluate the evidence for the effectiveness of intervention programs as they are routinely used in schools;
  2. Study changes in aggressive behavior over time periods covered by studies of school-based intervention programs, because the children exposed to these programs were in various developmental stages that may make aggressive behavior dynamic and undergoing.

Research Design

  • Number of Studies Included | 221
  • Number of Subjects | 56,000
  • Years Spanned | 1980-2003

Research Subjects
Children with behavioral problems.

Age/Grade of Subjects
Preschool to 12th grade.

Specified Disability
Behavioral Disorders,* Aggressive behavior including physical aggression, externalizing problems, fighting, bullying, acting out, disruptiveness, and conduct and discipline problems.

The interventions were delivered by teachers and researchers and in several formats. 67% were administered to groups of students, a little more than half of those in regular classroom settings, and 14% of the interventions used a one-on-one format with a student and provider. The intervention was described by coding the type of programs into the following categories:

  1. Social competence training without a cognitive behavioral* or behavioral component,
  2. Social competence training with cognitive-behavioral components,
  3. Behavioral and classroom management techniques,
  4. Therapy or counseling services,
  5. Separate schooling/ schools-within-schools, peer mediation,
  6. Academic and educational services,
  7. Multimodal.*

Duration of Intervention

  • The duration of most programs was less than 20 weeks.
  • 20% of the interventions lasted less than 7 weeks.
  • Some covered more than a school year, approximately 38 weeks.
  • Within these time periods, 52% of the intervention groups had program contact once or twice a week, with a majority involving less than 50 hours of total contact time.
  • The time interval between pre-test and posttest ranged widely from less than 6 weeks to more than a full school year, with a median of about 17 weeks.


  • The most outstanding characteristic of the outcome research on school based interventions is that they deal primarily with the results of demonstration programs.
  • There is little information about the effects of programs implemented by schools. The data available, suggests that those practice programs have minimal effects on the aggressive behavior they target.
  • Regardless of the fact that demonstration programs are not representative of routine practice programs, they produced encouraging evidence about what practice programs might achieve under favorable circumstances.
  • Youth in untreated control groups, showed little change on levels of aggressive behavior even across different levels of risk and different ages.
  • The role of school-based programs is primarily to reduce the levels of aggression that are already occurring, rather than preventing potential increases. Programs are most effective in contexts where the base rates of aggressive behavior are high enough for meaningful reduction to be possible.
  • Regardless of student characteristics, school-based interventions to reduce aggressive behavior were positive, however, the type of intervention did affect the overall success of the intervention.
  • Behavioral and counseling approaches showed the largest effects followed closely by social competence training with and without cognitive behavioral components. Multimodal and peer mediation programs showed the smallest effects.
  • Interventions were generally more effective when they were implemented well and relatively intensely, used one-on-one formats, and were administered by teachers.

Combined Effects Size
The mean* difference between pre-test and post-test change for intervention and control groups for all demonstration programs produced an estimate of 0.25 for the effect size* on aggressive behavior.

There was not enough evidence about the effectiveness of routine practice programs to support any solid conclusions. Research suggests that in order to be successful in implementing programs, service delivery personnel should be trained, supervised and have support. Compared to the routine practice programs, demonstration programs showed significant researcher involvement in training and supervision of delivery personnel. Future research should conduct more controlled evaluations of routine programs in school settings.


* Terms Defined

Behavior Disorders (BD) | A term used for children who have severe, persistent difficulties with social interactions and inappropriate behavior.

Cognitive-behavioral interventions (CBI) | CBI is a broad term that encompasses cognitive-behavioral modification (CBM) and cognitive-behavioral therapy (CBT). It is a behavior modification approach that promotes self-control skills and reflective problem-solving strategies. Interventions combine elements of behavior therapy (modeling, feedback, reinforcement) with cognitive approaches (problem solving, self-monitoring, self-instruction, communication skill building, relaxation, and situational self-awareness training) to teach individuals to recognize difficult situations, think of possible solutions, and select the most appropriate response.

Effect size (ES or d) | A statistical calculation, often represented as ES or d, that measures the impact of an intervention. An effect size below d = 0.20 suggests that a treatment did not have a significant effect. An effect size of d = 0.20 is considered small or low; an effect size of d = 0.50 is considered moderate; an effect size of d = 0.80 or above is large.

Mean (a.k.a. Average) | A measure of central tendency, calculated by dividing the sum total of a set of numbers by the number of figures in the set (e.g., of the set 5, 6, 8, 10, the average is 7.25. This number is derived by: 5+6+8+10=29, 29 divided by 4= 7.25.

Meta-analysis | A widely-used research method in which (1) a systematic and reproducible search strategy is used to find as many studies as possible that address a given topic; (2) clear criterion are presented for inclusion/exclusion of individual studies into a larger analysis; and (3) results of included studies are statistically combined to determine an overall effect (effect size) of one variable on another.

Multimodal | A program that incorporates several aspects of the subject being studied (e.g. a social skills training which incorporates elements of behavioral interventions, social problem solving, perspective-taking, or self-control interventions).

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