Design and methodology of a cluster-randomised controlled trial on cash plus interventions for preventing child...

Somalia is a conflict, flood, and drought prone country with high rates of food insecurity and child wasting. Save the Children partnered with Johns Hopkins University to study the most effective and cost-effective combinations of assistance to prevent acute malnutrition among pregnant and lactating women (PLW) and children under five (CU5) in a six-month humanitarian programme. This study implemented an cluster-randomised controlled trial (RCT) using adaptive design methodology to: (1) estimate and compare wasting incidence and prevalence of CU5 and their mothers receiving on a monthly basis either cash (Arm 1), cash + social and behaviour change communication (Arm 2), or cash + top-up cash (Arm 3); after three months and six months; (2) calculate the costs and cost-effectiveness of the different intervention arms; (3) understand perspectives and experiences of mothers and fathers of CU5 beneficiaries; (4) monitor the functionality of markets and availability and prices of foods. This paper presents the approach that was designed and implemented to study these objectives.

This study employed a mixed-methods approach with a quantitative component conducted at three time points to collect anthropometric measurements and household survey data. Primary outcomes, such as child and maternal wasting, were assessed using standardised World Health Organization criteria. Additional data on food security, maternal and child health, and household conditions were collected to evaluate immediate, underlying, and basic causes of malnutrition. Cost analyses evaluated programmatic and societal costs of the intervention. An adaptive trial design was implemented, allowing the methodology to evolve as new challenges emerged.

This trial applied an adaptive mixed methods design to evaluate the effectiveness and cost-effectiveness of cash assistance interventions in Somalia, overcoming complex humanitarian operational challenges. Strong partnerships and flexible trial design allowed us to adjust to unpredictable events and maintain research rigor. These findings highlight the value of adaptive designs and mixed methods for improving child nutrition outcomes in complex settings.

The cluster-RCT is registered at ClinicalTrials.gov, ID: NCT06642012.