20 Years of the Evidence Base on What Works to Prevent Child Marriage: A Systematic Review

"What interventions are effective in delaying age at marriage or reducing child marriage incidence among girls aged 10-24 years as assessed in experimental and quasi-experimental studies?"

Data published between 2018 and 2020 indicate that 1 in 5 girls are married as children annually, and 650 million women and girls currently alive were child brides. Although child marriages occur across the globe, 90% of the burden is in low- and middle-income countries (LMICs). An estimated 120 million girls are at risk of child marriage over the next decade, and progress would have to increase 12-fold to achieve target 5.3.1 of the Sustainable Development Goals (SDGs) by 2030. Thus, policymakers are looking for recommendations on programmes that are not only effective but can consistently reach large numbers of girls in the most affected countries. This review assesses evaluations published from 2000 to 2019 to shed light on what approaches work, especially at scale and sustainably, to prevent child marriage in LMICs.

The researchers conducted a search of electronic databases and gray literature and evaluated the methodological quality and risk of bias of the studies that met inclusion criteria. In all, they included 34 studies published between 2000 and 2019, covering 30 distinct evaluations of child marriage prevention programmes implemented in LMICs.

Table 1 in the paper provides a summary description of the characteristics of the included studies, and Table 2 provides more specifics on the interventions. Both tables are organised first by the 2 broad categories of interest: multicomponent (11 studies) and single component (including 10 programme interventions and 2 macro policies) (12 studies). They also include a third category of 7 multiarm studies, which evaluated both multi- and single-component interventions. Here is an example of data to be found in these tables: a cluster RCT study of 4,000 Indian women aged 15-21 years, involving 160 study and control villages, found a 5.1% lower likelihood of marriage for programme participants in 3 years of intervention through efforts to increase job opportunities to improve female early life outcomes.

As the variation in outcome measures on child marriage reduction used across studies did not permit the assessment of study results using a common measure, the researchers considered a study as demonstrating a positive impact if its results found the intervention to successfully prevent early or child marriage and were statistically significant (p < .05).

Most of the multicomponent (8/11) and single-component (8/12) studies used a quasi-experimental design, with cluster randomised controlled trials (RCTs) a less frequent occurrence. Four of the 7 multiarm studies, on the other hand, were RCTs. Multicomponent studies were much more likely to be low quality (7/11), whereas there were no low-quality single-component studies and only 1 low-quality multiarm study.

The researchers used a reach of 25,000 participants as a conservative threshold for scale. Only 2 of the 11 multicomponent interventions met this threshold, and only 1 of the 7 multiarm programmes did so. In contrast, 9 of the 12 single-component interventions reached 25,000 or more participants, with 8 of these 9 programmes reaching several hundred thousand or even millions of participants. Furthermore, the single-component programmes show a better sustainability record (8/12) than the multicomponent (2/11) and multiarm (1/7) programmes.

Tables 3A, 3B, and 3C in the paper present findings from the 30 studies with regard to impact on child and early marriage prevention, separately for multicomponent, single component, and multiarm interventions, and by subcategories within these groupings. In terms of approaches, the review found that interventions that support girls' schooling through cash or in-kind transfers show the clearest pattern of success in preventing child marriage, with 8 of 10 medium-high quality studies showing positive results. Although limited in number, 5 studies on favourable job markets and targeted life skills and livelihoods training show consistent positive results. Comparatively, asset or cash transfers conditional on delaying marriage show success only among 2 of 4 evaluations, and the 3 studies on unconditional cash transfers for poverty mitigation show no effect.

Table 4 provides a comprehensive summary of success rates for different subcategories of interventions across all studies, both with and without sensitivity analysis. One insight: The findings show a low success rate for multicomponent interventions, with positive results in only 1 of 8 medium-high quality studies.

In short, the results indicate that enhancement of girls' own human capital and opportunities is the most compelling pathway to delaying marriage. This conclusion is also supported by a high share of positive results among the few studies that assessed an exclusive focus on life skills, livelihoods, and gender rights training for girls. Besides their effectiveness, a more significant share of targeted interventions that enhance girls' human capital and their employment opportunities operate at scale. For example, 4 of the 8 programmes with positive results on conditional cash transfers (CCTs) for school support were large-scale government-implemented efforts, reaching many thousands or even millions of girls. Similarly, macro policies supporting female employment in the garment industry in Bangladesh or the outsourcing boom in India also affected girls and young women in very large numbers. "From the available evidence, these two intervention approaches demonstrate a combination of success as well as scale and sustainability more extensively than any other category of interventions."

In contrast, low rates of success, scale-up, and sustainability of multicomponent programmes require reconsideration of this approach. Multicomponent programmes that do not take the empowerment approach are even less successful. "More systematic documentation and analysis of implementation processes are needed to better understand why multicomponent programs are not succeeding at higher rates."

The researchers conclude that, in considering school-focused CCTs and female-centred employment policies, "it will be important to explore how child marriage prevention might be integrated as a central rather than peripheral focus in such interventions and policies....Moreover, the success of demand-side interventions to promote girls' schooling through cash and in-kind support begs the question of the potential positive effects of supply-side interventions for girls' schooling, such as more secondary schools or female teachers, better curricula and skills, or more accessible transportation."