The authors concluded that the Drug Abuse Resistance Education programme had consistent less than small effects on drug use and inconsistent less than small effects on psychosocial behaviour. The authors’ conclusions appear to reflect the evidence, but incomplete reporting of the review methods and a lack of information on the included studies mean that their reliability is unclear.

To evaluate the effectiveness of the Drug Abuse Resistance Education (D.A.R.E.) programme in the USA.

PubMed, PsycINFO, ERIC, Social Sciences Index, Social Sciences Citation Index, and Digital Dissertations Online were searched for studies published between 1983 and December 2005. Search terms were reported.

Experimental and quasi-experimental studies with a comparable control group that evaluated the D.A.R.E. programme were eligible if they assessed drug use or psychosocial behaviour and reported sufficient data to allow the calculation of an effect size.

Where reported, the percentage of female participants ranged from 48 to 59, the percentage of white participants from 40 to 90, and the percentage of black participants from 6 to 50. The year of the D.A.R.E. programme ranged from 1985 to 1999. No details of the control interventions were reported.

The authors did not state how papers were selected for the review.

The authors did not state that they assessed validity.

Effect sizes (Cohen’s d) were calculated separately for all the reported drug use outcomes and all the psychosocial behaviour outcomes, for the longest follow-up available. The methods used to deal with multiple measures in individual studies were not reported.

Two reviewers independently extracted the data and disagreements were resolved by discussion.

A pooled unweighted mean effect size was calculated for drug use and for psychosocial behaviour. The pooled 95% confidence intervals were calculated, but were not displayed in the forest plots and were not reported. Heterogeneity was assessed using the Cochran Q statistic. Where significant heterogeneity was found, a random-effects model was used to calculate the weighted mean effect size. Forest plots of effect sizes were presented. Weighted regression analysis was used to examine the sources of heterogeneity from the duration of follow-up, statistical method, D.A.R.E. year, and the proportion of white and black participants; where studies had missing data, the mean values were used.

Twenty studies were included, with 30,229 participants. Five studies used multilevel models, five used general linear models and the others used descriptive statistics. No other details of study design were reported. The duration of follow-up ranged from none to 10 years.

Drug use: The unweighted mean effect size for drug use was 0.05 (range -0.08 to 0.36). This effect size was less than small according to Cohen’s classification. No significant statistical heterogeneity was found.

Psychosocial behaviour: The unweighted mean effect size for psychosocial behaviour was 0.10 (range -0.09 to 0.38). This effect size was less than small according to Cohen’s classification and significant statistical heterogeneity was found (p<0.0001).

The regression model: Found that five characteristics accounted for most of the heterogeneity. Longer follow-up time (p<0.02) and more rigorous statistical methods (p<0.001) were associated with a reduced intervention effect. Later D.A.R.E. year (p<0.02) and more white (p<0.002) and more black participants (p<0.03) were associated with an increased intervention effect.

The D.A.R.E. programme had less than small effects on drug use and psychosocial behaviour. The results were consistent across studies for drug use, but not for psychosocial behaviour and these differences were explained by the study characteristics.

The review question was clearly stated and the inclusion criteria were specified for the intervention and outcome and broadly defined for study design. Several relevant sources were searched. Attempts appear to have been made to minimise publication bias, but it was not clear if they were made to minimise language bias. Methods were used to minimise reviewer errors and bias in the extraction of data, but it was not clear whether similar steps were taken in study selection. Study validity was not assessed, very little information was provided about study design, and no information was given about the methods used to assess outcomes, which means that the results from these studies and any synthesis might not be reliable. The studies were combined using meta-analysis and potential sources of heterogeneity were explored.

The authors’ conclusions appear to reflect the evidence, but incomplete reporting of the review methods and a lack of information on the included studies especially study quality mean that the reliability of the findings is unclear.

Practice: The authors did not state any implications for practice.

Research: The authors stated that a follow-up meta-analysis on the effectiveness of the new D.A.R.E. programmes should be conducted.

Not stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.