Modality of and Adherence to the Intervention Promoting Household Water Treatment and Safe Storage: A Study Design of RCT in Uganda

Unlike medical interventions, recipients of foreign aid are not typically consulted repeatedly after the intervention, which means adherence to the intervention depends entirely on the recipients despite its crucial role in determining whether the intervention bears fruit or withers away to nothing. Therefore, identifying a modality of intervention that can maximize recipients’ adherence is critical to the efficiency of development aid.

This presentation outlines the design of a randomized controlled trial, scheduled for August 2025 in Uganda, which will empirically test whether a hands-off strategy improves adherence to the intervention compared to the more conventional hands-on approach in the context of the Household Water Treatment and Safe Storage (HWTS) assistance. In this study, the hands-on approach involves encouraging water boiling by providing instructions and materials, while the hands-off approach involves transferring cash equivalent to the cost of the hands-on intervention, conditional on the presence of disinfected drinking water, which is objectively judged by the number of colonies of E. coli and total coliforms. Both interventions are implemented for two weeks in person and by phone. The primary outcome is the extent to which participants continue disinfecting drinking water - by boiling or other methods of their choice- after the two-week intervention.

Adherence is measured in two ways. First, at two separate time points after the intervention, adherence is assessed through objective tests of drinking water (as previously mentioned) and participants' self-reports during unannounced visits. Second, adherence between the two visits is quantified by the number of ticks on a calendar provided to participants for self-monitoring during the intervention, which they are encouraged to continue using after the intervention ends.