Description of hypothesised interventions, their duration, and staffing structure.

Description of hypothesised interventions, their duration, and staffing structure.</p

S1 Fig -

Cost-effectiveness plane scatter plots of costs per adolescent over effectiveness (in DALYs averted) for four scenarios with the SA GDP per capita as the willingness-to-pay threshold at: A) Routine service costing and population-average prevalence of violence, B) Routine service costing and high prevalence of violence, C) Trial-based costing and population-average prevalence of violence, and D) Trial-based costing and population-high prevalence of violence. (DOCX)</p

Fig 2 -

Cost-effectiveness plane scatter plots of costs per adolescent over effectiveness (in DALYs averted) for four scenarios at A) Routine service costing and population-average prevalence of violence, B) Routine service costing and high prevalence of violence, C) Trial-based costing and population-average prevalence of violence, and D) Trial-based costing and population-high prevalence of violence. Diagonal lines indicate an evidence-based SA-specific willingness to pay threshold for health interventions estimated by Edoka and Stacey, 2020. Strategies become increasingly cost-effective as they lie to the north easternmost part of the cost-effectiveness plane below the willingness to pay threshold. Strategies above the line are not cost-effective at the stated threshold. Abbreviations: DALYs, disability-adjusted life years; USD, United States dollar.</p

Cost-effectiveness plane scatter plots of costs per adolescent over effectiveness (in DALYs averted) for four scenarios using estimates for the relationship between household income and food security drawn from secondary analysis of the South Africa’s 2018 GHS.

The SA-specific threshold per capita is used as the willingness-to-pay threshold at: A) Routine service costing and population-average prevalence of violence, B) Routine service costing and high prevalence of violence, C) Trial-based costing and population-average prevalence of violence, and D) Trial-based costing and population-high prevalence of violence. (DOCX)</p

Synthesis of the effect of cash grants on household food insecurity in sub-Saharan Africa.

Synthesis of the effect of cash grants on household food insecurity in sub-Saharan Africa.</p

Summary of the estimated cases of violence victimisation, DALYs averted, costs, and cost-effectiveness ratios of intervention scenarios over a ten-year time horizon.

Summary of the estimated cases of violence victimisation, DALYs averted, costs, and cost-effectiveness ratios of intervention scenarios over a ten-year time horizon.</p

Detailed breakdown of the cost of grant outreach, parenting support, and parenting support plus grant linkage in United States dollars.

Detailed breakdown of the cost of grant outreach, parenting support, and parenting support plus grant linkage in United States dollars.</p

Analysis of the relationship between household income and food security in South Africa using data from the 2018 General Household Survey.

Analysis of the relationship between household income and food security in South Africa using data from the 2018 General Household Survey.</p

Summary of key model inputs, their description, and source.

Summary of key model inputs, their description, and source.</p

CHEERS checklist.

There is limited evidence around the cost-effectiveness of interventions to reduce violence against children in low- and middle-income countries. We used a decision-analytic model to evaluate the cost-effectiveness of three intervention scenarios for reducing adolescent emotional, physical, and sexual abuse in Mpumalanga Province, South Africa. The intervention scenarios were: 1) Community grant outreach to link households to South Africa’s Child Support Grant (CSG) if they are eligible, but not receiving it; 2) Group-based parenting support; and 3) Group-based parenting support ‘plus’ linkage to the CSG. We estimated average cost-effectiveness ratios (ACERs) for intervention scenarios over a ten-year time horizon, and compared them to a South Africa-specific willingness-to-pay (WTP) threshold (USD3390). Health effects were expressed in disability-adjusted life years (DALYs) averted. Our model considered four combinations of routine service versus trial-based costing, and population-average versus high prevalence of violence. Under routine service costing, ACERs for grant outreach and parenting support were below the WTP threshold when considering a population-average prevalence of violence USD2850 (Lower: USD1840-Upper: USD10,500) and USD2620 (USD1520-USD9800) per DALY averted, respectively; and a high prevalence of violence USD1320 (USD908-USD5180) and USD1340 (USD758-USD4910) per DALY averted, respectively. The incremental cost-effectiveness of parenting support plus grant linkage relative to parenting support alone was USD462 (USD346-USD1610) and USD225 (USD150-USD811) per DALY averted at a population-average and high prevalence of violence, respectively. Under trial-based costing, only the ACER for grant outreach was below the WTP threshold when considering a high prevalence of violence USD2580 (USD1640-USD9370) per DALY averted. Confidence intervals for all ACERs crossed the WTP threshold. In conclusion, grant outreach and parenting support are likely to be cost-effective intervention scenarios for reducing violence against adolescents if they apply routine service costing and reach high risk groups. Combining parenting support with grant linkage is likely to be more cost-effective than parenting support alone.</div