The main objective of this review is to assess the available research evidence on the effect of self-control improvement programs on self-control and delinquency and problem behaviors. In addition to investigating the overall effect of early selfcontrol improvement programs, this review will examine, to the extent possible, the context in which these programs may be most successful.
Several strategies were used to perform an exhaustive search for literature fitting the eligibility criteria: (1) A keyword search was conducted across a number of online abstract databases; (2) The reference lists of previous reviews of early childhood prevention/intervention programs in general and self-control improvement programs specifically were consulted; (3) Hand searches were carried out on leading journals in the field; (4) The publications of research and professional agencies were searched; and (5) Recognized scholars (experts) in various disciplines who were knowledgeable in the specific area of self-control improvement programs were contacted.
Studies that investigated the effect of early self-control improvement programs on improving self-control, and/or reducing delinquency and problem behaviors were included. Studies were only included if they had a randomized controlled evaluation design that provided post-test measures of self-control and/or delinquency and problem behaviors among experimental and control subjects.
Narrative findings are reported for the 34 studies included in this review. A metaanalysis of all 34 of these studies was carried out. The means and standard deviations were predominantly used to measure the effect size. Results are reported for the unbiased effect sizes and the weighted effect sizes and, where possible, comparisons across outcome sources (parent-reports, teacher-reports, directobserver reports, self-reports, and clinical reports). Bivariate and multivariate analyses (using Lipsey &Wilson's SPSS macros) are performed in an effort to determine potential moderators and predictors of the effect sizes, respectively.
The studies included in this systematic review indicate that self-control improvement programs are an effective intervention for improving self-control and reducing delinquency and problem behaviors, and that the effect of these programs appears to be rather robust across various weighting procedures, and across context, outcome source, and based on both published and unpublished data.
We conclude that self-control improvement programs should continue to be used to improve self-control and reduce delinquency and behavior problems up to age 10, which is the age cutoff where Gottfredson and Hirschi argue that self-control becomes relatively fixed and no longer malleable. Considering these results, future efforts should be made to examine the effectiveness of self-control improvement programs over time and across different segments of the life-course (e.g., midadolescence, young adulthood etc.), and conduct rigorous cost-benefit analysis on programs such as these.