Transcript Family-based Prevention of Offending: A Meta

Family-based Prevention of
Offending: A Meta-Analysis
David P. Farrington & Brandon C. Welsh
2003
Jenna Ayers
Radford University
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.
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)
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
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
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
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
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
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)
Meta-Analysis
Mean Effect Sizes
Category
A
B
C
D
E
F
Total
Low CI
.111
.147
.274
-.014
.056
.281
.278
High CI
.360
.371
.517
.149
.306
.548
.269
Mean
.235
.259
.395
.068
.181
.414
.223
Sig
2/4
4/5
5/10*
3/7
3/8
2/6*
19/40*
Mean Effect Sizes
Delinquency
Short-term
Long-term
Total
Low CI
.132
.281
.250
High CI
.315
.464
.391
Mean
.224
.372
.321
Sig
5/12
6/10
10/19*
.157
.016
.146
.252
.201
.246
.204
.109
.196
11/26
2/7
11/27
Antisocial
behavior
Short-term
Long-term
Total
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
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
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
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
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
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.