Evidence-based public health o Harcourt Brace and Company Limited 1997

A violence prevention curriculum in secondary schools was associated with a moderate decrease in physically aggressive behavior and an increase in neutral and pro-social behavior among schoolchildren

Grossman D C, Neckerman H J, Koepsell T D et al. Effectiveness o fa violenceprerention curriculum among children in elementary school JAMA 1997; 277: 1605-16I 1

Objective

To evaluate the effects of the 'Second Step' violence prevention curriculum on the prevalence of 'aggressive' and 'pro-social' behaviors among elementary schoolchildren.

Setting

Urban and suburban schools in Washington State, USA.

Method

Randomized-controlled trial. An educational program, Second step: a Violence Prevention Curriculum, designed to reduce aggressive behavior and increase pro-social behavior, was selected for use. 12 elementary schools in four school districts in King County, Washington, were selected. Schools were paired according to the environment and the proportions of students receiving free or reduced-cost school lunches and ethnic

minority groups. After matching, schools in each pair were randomly assigned as either 'intervention' or 'control' schools. 49 classes were eventually included in the study. The pupils were in the second and third grades (age 10--12).

The observers making the recordings of the behavior on the playground were 'blinded' that is they were unaware of the study purposes, hypothesis and research design.

Literature review

No explicit strategy stated; 46 references.

Outcomes measures

I. Aggressive behavior 2. Pro-social behavior.

These were assessed by parents, teachers and by observation of a random sample of 588 students in classroom and playground settings.

Results

Because schools rather than students were randomized, special statistical techniques were used to allow for the relatively small number of units being studied, i.e. the 49 classes, to be analyzed.

After taking into account gender, age, socio-economic status, race, academic performance, household size and class size, the measures of aggressive and pro-social behavior did not differ significantly between the intervention and control schools when the reports of parents and teachers were used as the criteria to measure change. However, the direct observations revealed an overall decrease in physical aggression and an increase in neutral or pro-social behavior in the intervention group 2 weeks after the curriculum. The statistical significance of the differences were not strong (P < 0.3 and 0.4, respectively). Most of the effects persisted 6 months later.

Authors' conclusions

The authors emphasized the limitations of their study and the factors that might explain the differences observed, other than the effect of the intervention, but conclude that the violence prevention curriculum 'appears to lead to modest reductions in levels of aggressive behavior and increases in neutral behavior' in school. They emphasize that although their results are 'encouraging,' isolated interventions may be relatively ineffective and may need to be complemented by other types of intervention at other ages and in other settings.

Conlmen taFy

Teenage violence is an increasingly important problem in many countries. Although the homicide rate in children and teenagers in the USA is 18 times the rate in Britain, mostly due to the difference in firearm deaths, over the past decade teenage homicide rates in England and Wales have increased by over 70%. The paper by Grossman et al addresses an important public health problem using the rigorous epidemiological design of the randomized- controlled trial.

They found that the Second Step violence prevention curriculum resulted in a moderate observed decrease in aggressive behavior and an increase in pro-social behavior. It is

clear from the discussion section that this is not the first randomized trial of a violence prevention curriculum.

Although the results of this study are encouraging, it would be inappro~iate to base policy on the results of this study alone. Instead, policy should be based on a systematic review of all relevant randomized-controlled trials, whether published or unpublished, that have evaluated the effectiveness of violence prevention curricula. If this supports the conclusion of the present "study, the next policy question would be to ask whether the benefits to society of implementing the curriculum exceed the costs. However, typically cost-benefit information is not

readily available and so the question becomes one of relative cost-effectiveness compared with other educational interventions. That the violence prevention curriculum would compare favorably would seem quite plausible. Indeed, bearing in mind that most of what goes on in schools has never been rigorously evaluated, there is likely to be more evidence to support the violence prevention curriculum than, for instance, the geography or history curricula.

Dr Ian Roberts Director, Child Health Monitoring Unit

hlstitute of Child Health London, UK

DECEMBER 1997 EVIDENCE-BASED HEALTH POLICY AND MANAGEMENT 87