Introduction
Child physical abuse is defined as the intentional use of physical force against a child, including hitting, beating, kicking, shaking, biting, scalding, burning, poisoning, and suffocating, often performed under the guise of discipline or punishment (WHO
2006). Worldwide cross-sectional surveys estimate that nearly one in four adults report experiencing physical abuse as children (WHO
2014; Butchart and Mikton
2014). Recent data from Egypt, India and the Philippines indicate that, in these countries, 26, 36 and 21% of parents, respectively, report hitting children with an object as a form of punishment (WHO
2014). Estimates of violence against children, which includes moderate to severe physical abuse, find that a minimum of 64% of 2–17-year-old children in Asia, 56% in Northern America, 50% in Africa, 34% in Latin America, and 12% in Europe experienced some form of violence in the last year (Hillis et al.
2016). These prevalence rates are not only high—they are also likely to be underestimates, as measurement errors, stigma and social normativity tend to mask the true magnitude of the problem (Finkelhor et al.
2014; Townsend and Rheingold
2013; Cicchetti and Toth
2005). Physical violence in particular is rarely reported and largely hidden: prevalence of physical abuse is over 75 times higher when assessed with victims’ self-reports rather than official reports (Stoltenborgh et al.
2013); and only the most severe cases tend to come to the attention of Child Protection authorities, if such authorities exist in the community at all.
The societal burden of child physical abuse is exorbitant—the lifetime economic cost for all new cases of abuse in one calendar year in the US has been estimated at $124 billion (Fang et al.
2012). Global estimates of the cost of this type of abuse in particular are not yet available, but a recent economic evaluation of the damage of violence against children (combining physical, psychological and sexual abuse only) has set the figure at $7 trillion, or up to 8% of global GDP (Pereznieto et al.
2014). The consequences of child physical abuse are costly, numerous, and severe—physical injury, disability, poor cognitive and socio-emotional outcomes, behavioral and mental health problems throughout the lifespan, perpetuation of abuse cycles, and even death are linked to having experienced abuse as a child (Gilbert et al.
2009; Gershoff
2010; Holmes et al.
2005; Repetti et al.
2002; Runyon et al.
2004; UNICEF
2006). While milder forms of physical abuse might have impairing consequences, there is an established dose–response relationship between experience of physical abuse in childhood and poor outcomes—that is, the most severe and persistent experiences of physical abuse are associated with the poorest outcomes (Norman et al.
2012). It is also known that violence breeds more violence, even across generations—children who have experienced physical abuse are most at risk of re-experiencing it (Hindley et al.
2006); and parents with a history of abuse during childhood are twice as likely to be reported to CPS for child maltreatment (Widom et al.
2015). It is therefore of vital importance to find effective interventions to prevent the recurrence of child physical abuse and break this cycle of violence.
Parenting programs are one such intervention. They are aimed at improving the quality of the parent–child relationship and preventing re-abuse by changing parenting attitudes, practices, and skills, as well as reducing parent–child conflict, coerciveness and parenting stress, improving parental psychosocial functioning, improving family dynamics and reducing child behavior problems (Barlow et al.
2006a; Montgomery et al.
2009). These interventions are generally based on Attachment Theory (Bowlby
1969), Learning Theory (Skinner
1950), and/or Social Learning Theory principles (Bandura
1971), though the latter informs most parenting interventions aimed to reduce child abuse. Most central in this is Patterson’s (
1982) coercion hypothesis, which states that abuse might result from a repeating pattern of coercive parent–child interactions in which both the parent and the child escalate their violent behavior (Brinkmeyer and Eyberg
2003). On the side of the parent, the escalating coercive behavior springs from a belief that their child is defiant and unresponsive to less harsh forms of discipline. As children comply, parents may incorrectly believe that this strategy—and no other—works, and they therefore continue to use it (Crouch and Behl
2001). Parenting programs intend to break this cycle by promoting parental sensitivity, modifying parental attitudes, changing parental attributions, teaching adequate disciplining techniques, and increasing the use of positive parenting skills.
Prior reviews have found parenting programs to be promising strategies for reducing recurrence of child physical abuse. Four reviews in particular inspire the current review and meta-analysis. Barlow et al. (
2006b) conducted a high-quality systematic review of individual- and group-based parenting programs to prevent child physical abuse and neglect recidivism, and reduce risk factors associated with re-abuse. This synthesis of RCTs revealed that, overall, parenting programs are a promising treatment strategy for preventing new incidents of abuse in families with a history of physical abuse—but not neglect. Furthermore, parenting programs were found effective in reducing risk factors associated with re-abuse when delivered to families with suspected or substantiated history of abuse. However, because their search resulted in a highly heterogeneous and limited set of trials, authors elected against conducting a meta-analysis of outcomes.
Another systematic review focusing specifically on corporal punishment (i.e., physical pain applied to correct or punish a child’s behavior) was conducted in Brazil (Santini and Williams
2016). It found 18 studies using different methodologies to evaluate the effectiveness of parenting programs to reduce corporal punishment, with all studies reporting medium to large reductions (
d = .54–2.17). Nevertheless, the authors of this review also opted against conducting a meta-analysis at the time due to insufficient trial-level data reported by the included studies.
New evidence from the last decade has provided additional trials with enough clinical homogeneity to justify meta-analysis. Chen and Chan (
2015) conducted an updated review of parenting programs for the treatment of child abuse, and attempted a meta-analysis of abuse recurrence outcomes (among others), finding that parenting programs successfully reduced substantiated and self-reported child maltreatment reports
(d = .208). Parenting programs were also found to reduce risk factors—specifically ineffective parenting—and enhance protective factors such as endorsement of appropriate child-rearing attitudes, positive parenting, and parent–child interaction. However, given the clinical diversity of the interventions modalities included in their models, their meta-analyses also exhibited high degrees of statistical heterogeneity (
I
2 = 75.6;
p < .001), suggesting a need for a more tailored approach to understanding intervention modalities.
A systematic review and meta-analysis published in 2015 (Euser et al.
2015) identified 23 RCTs that tested the effect of 20 different programs (including but not limited to parenting programs) on child maltreatment prevention and/or reduction (including but not limited to physical abuse). It found a small but significant effect in favor of treatment (
d = .13, 95% CI [0.05, 0.21]), but again, statistical heterogeneity was too high to indicate the true effect of these programs (
Q = 56.06,
p < .01). Additionally, trim-and-fill analysis of publication bias found that, after adjusting the results of 9 studies with small sample sizes, the pooled effect was greatly diminished (
d = 0.02, 95% CI [−0.06, 0.11]), suggesting publication bias favoring the publication of smaller studies with significant findings.
Prior reviews suggest the potential effectiveness of indicated parenting programs to prevent child physical re-abuse. However, the body of evidence to date has not been large enough or evaluated with sufficient rigor to corroborate these findings. Additionally, the only meta-analyses that have been conducted (i.e., Chen and Chan
2015; Euser et al.
2015) suffered from problems resulting from a scope too wide and a level of heterogeneity too high to produce results with substantive value. The importance of conducting this review thus springs from two necessities: (1) to provide an up-to-date synthesis of the research on child physical re-abuse prevention using parenting programs, and (2) to overcome the methodological limitations that prior reviews have encountered by narrowing the scope of this review only to those interventions strictly based on SLT to enable combination of trial outcomes into a meta-analysis with less heterogeneity, thus producing a valuable reading of the cumulative evidence. The value of meta-analysis lies in its ability to estimate a mean effect of the interventions, thus providing a helpful basis by which to understand how effective programs could be when implemented in practice settings, and the degree to which new programs offer a meaningful advantage over existing interventions. Moreover, many reviews of complex interventions—such as parenting programs to reduce re-abuse—focus on a diversity of programs united by a similar theory of change (Bonell et al.
2016). This is an analytically helpful approach as it focuses on testing the underlying principles, which are thought to make interventions effective. In this study, we provide a broad test as to whether a theory of change, when implemented in the form of parenting interventions, has the potential to reduce recurrence of child maltreatment. Particularly, we focus on behavioral parenting programs (as opposed to non-behavioral programs, which might focus on transforming attitudes and attributions) to be better able to ascertain the effect of programs in this particular intervention modality without injecting problematic clinical heterogeneity in our collection of trials.
Discussion
This review was conducted to strengthen our understanding of the effectiveness of SLT-based behavioral parenting programs for preventing child physical abuse recurrence. Methodologically, it overcomes several important challenges encountered in prior reviews (e.g., Barlow et al.
2006b; Chen and Chan
2015), by including evidence from the last decade, selecting trials for inclusion with stringent criteria, and conducting an informative meta-analysis featuring limited statistical and clinical heterogeneity. The results of this review suggest that behavioral parenting programs are modestly but significantly effective strategies for reducing hard markers of recidivism in physically abusive families. Our meta-analysis found recidivism to be 11% lower for CPS referred families who received SLT-based behavioral parenting training. While this figure is modest, it is important to recognize its magnitude given the complicated nature of child welfare systems and the multiple high risks to which referred families tend to be exposed to. Granted, more extensive and better-quality research is needed to understand the effectiveness of this intervention modality, and thus establish its effectiveness more robustly. While we were only able to include four studies in the meta-analysis, a better-powered analysis may also have been able to understand not only whether this intervention modality is effective, but also the differences between specific interventions that might make them more or less effective.
A few limitations of this review must be highlighted. First, the included trials were conducted exclusively in the US or Canada. This is not uncommon in the field of child maltreatment: in a systematic review of reviews by Mikton and Butchart (
2009), it was established that 90% of trials of child maltreatment interventions were conducted in high-income countries. Orienting future systematic reviews to include trials in languages other than English might help ensure that research from other settings is captured, thus reducing the possibility that geographic homogeneity is an artifact of the search criteria. On the other hand, this review could serve as a starting point for a regional analysis of program effectiveness in this region. In that case, search criteria should be expanded to include child neglect, seeing as it is the mode reason for CPS reports in this region.
Second, only half of the included trials had a follow-up assessment, of which only 14% only followed participants for more than 6 months. Only one notably strong trial (Chaffin et al.
2012) had a longitudinal design, with a 6-year follow-up period. Longer follow-up periods in other similar trials would be necessary to understand the long-term effects of parenting programs.
Third, some decisions made during the selection of studies for inclusion might have introduced bias in this review. For instance, one of the included trials (Chaffin et al.
2012) barely met participant inclusion criteria—the proportion of physically abusive parents was 14% instead of the set minimum of 15%. However, given that only 1% was missing in this instance, an exception was made. Another exception was made for the MacMillan et al. (
2005) trial, where the number of physically abusive parents was not reported, but the overall quality of the trial and perfect fit with other inclusion criteria prompted its exceptional inclusion. Future reviews should revisit the conceptual framework for setting the thresholds for inclusion at 15%, considering the low reporting rates for this specific type of abuse.
Lastly, while the statistical heterogeneity in the meta-analysis was low, the clinical heterogeneity present in the set of included studies might need to be carefully considered. The interventions grouped under the umbrella category “parenting programs” included a diversity of components, dosages, delivery settings, and other elements. Nonetheless, this variability is advantageous for the purposes of exploring the effectiveness of the theory of change (i.e., the underlying principles of SLT-based programs), as opposed to any one particular intervention modality or program. This said, when the evidence base is large enough, future reviews should include subgroup analysis so as to better understand how intervention and participant characteristics might be influencing the observed effect. For instance, it would be interesting to explore the differential effects that parent training might have on different types of families (e.g., families with substance abuse issues, single-parent families). Meta-analyses of pooled individual-level data from trials on parenting programs could elucidate differences between types of participants in subsequent synthesis efforts.
Future research should also focus on understanding how parenting programs work and how their effectiveness can be improved, by exploring the specific mechanisms through which programs reduce or prevent child maltreatment. This is because parenting interventions are complex intervention packages that include multiple interacting components related to parenting knowledge, principles, and skills (Kaehler et al.
2016). Knowing which core components are driving effectiveness can help optimize interventions by making them briefer, more effective and cost-effective, and improving implementation, reach, uptake, replicability, and sustainability of effects (Elliott and Mihalic
2004; Leijten et al.
2015, Glasziou et al.
2008; Linnan and Steckler
2002). Bentovim and Elliott (
2014) initiated the important task of identifying core components of parenting interventions by employing a “distillation and matching” technique on a few selected RCTs that found parenting training effective for the treatment of physical abuse recidivism. Methodologies such as meta-analysis of components (e.g., Kaminski et al.
2008) could also be used in this context to systematically and retrospectively explore which intervention components are related to the strongest effect sizes.
This review ought to be replicated and updated as more and better-quality evidence becomes available. However, at present, it is defensible to conclude that targeting the parent–child relationship through SLT-based behavioral parenting programs can be an effective treatment for preventing recurrence of child physical abuse—at least in a North American context.