Family-based Prevention of Offending: A Meta-Analysis

1. Family-based Prevention of Offending: A Meta-Analysis David P. Farrington & Brandon C. Welsh 2003 Jenna Ayers Radford University

2. Overview • Review of the effectiveness of family-based prevention programs in reducing offending and antisocial behavior by children and adolescents. • Family-based programs typically target family risk factors. • Goal: aims to prepare and maintain systematic reviews and to make them available electronically.

3. Previous Research • Narrative reviews of effect of family-based interventions to prevent delinquency and later criminal offending • Serketich & Dumas (1996) • Cochrane review completed by Woolfenden, Williams, & Peat (2002)

4. Systematic Review Why? • Use rigorous methods for: locating, appraising, and synthesizing evidence from evaluation studies • Explicit objectives • Explicit criteria for inclusion and exclusion of studies • Wide-ranging methods for searching for studies that are designed to reduce bias

5. Method • Selection of Evaluations (Inclusion) • 1. The family and family factors • 2. Outcome measure of delinquency or antisocial child behavior • 3. High quality methodologically • 4. Original sample size

6. Searching Strategies • Original aim: to update the review of family-based crime prevention in the 1997 Maryland Report • Began searches in 1997 • 1. Recent reviews • 2. Articles in major journals • 3. Youth Update • 4. Contacts

7. Measuring Effect Size • Aimed to measure 4 different effects in each study: • 1. Short-term effect on delinquency • 2. Short-term effects on child antisocial behavior • 3. Long-term effects on offending • 4. Long-term effects on antisocial behavior

8. Main Measure of Effect Size The standardized mean difference d, which summarizes the difference between the experimental and control groups in standard deviation units: • D= (Mc-Me)/s • Positive value of d indicates a desirable effect of the intervention

9. Family-based Prevention Programs • Home Visiting (4) • Day Care/Preschool programs (5) • Parent Training programs (10) • School-based programs (7) • Home/Community programs with Older Children (8) • Multi-systemic Therapy Programs (6)

10. Meta-AnalysisMean Effect Sizes

11. Mean Effect Sizes

12. Results of Meta Analysis • Suggest that prevalence of offending could be reduced by about 10-15% by implementing such programs. • More than half of all evaluations found a significant decrease in delinquency • Effects on delinquency persisted in long-term evaluation studies

13. Results • Most effective types of programs used behavioral parent training • Least effective were those based in schools • All other types of family-based programs were effective

14. Conclusions • 40 of the highest quality family-based crime prevention programs were reviewed • Programs grouped into 6 categories • These family-based programs had desirable effects in reducing delinquency and antisocial child behavior

15. Future Research • More large-scale evaluations are needed using randomized experiments • Ideally, programs focusing more clearly and more narrowly on family risk factors should be implemented and evaluated • More efforts should be made to determine links in the causal chain between family processes and offending • More long term follow ups should be carried out to establish the persistence of effects

16. Future Research • Important to investigate why effect sizes are greater in smaller scale studies than in larger scale ones. • Future experiments needed that attempt to disentangle the different elements of successful programs • Know more about the economic efficiency of family-based crime prevention programs

17. Bottom Line • Existing evidence suggests that family-based prevention programs are effective in reducing offending. • More of these types of programs should be implemented and evaluated.