Data Collection
We captured all service delivery costs, regardless of funding source (e.g., research grant, Uganda Ministry of Health [MOH], other), to better understand the costs of implementation by each mode of booster delivery, separating costs for interventions with boosters delivered by live counselors, IVR, and SMS. We collected costing data between November 2019 and March 2021. We used e-mail and phone conversations to elicit costs for office equipment and training from the MUST Grants Office finance staff and local salary costs from the local investigator and study coordinator. We used a tracking log to record hours worked and distribution of effort by the intervention counselors. Counselor effort included time spent preparing for sessions with participants, in-person counseling sessions, booster phone calls, and administrative activities such as scheduling appointments and organizing session notes. We recorded the effort of other intervention staff such as the data manager and study coordinator; we limited this to activities directly related to the intervention and excluded time spent on research activities adapting the intervention and conducting the RCT. We used a standard exchange rate from September 1, 2019, of 1 US dollar to 3690 Ugandan Shillings. All information was then reviewed with study staff and investigators to double-check accuracy.