Tools
We used standard costing tools for intervention delivery type cost comparisons. These included data collection spreadsheets for the in-person counseling component of the intervention (which was identical across all booster session delivery types) and for the booster sessions (either live call, SMS, or IVR sessions, analyzed separately here) that we adapted from past costing efforts. We also reviewed counselor tracking logs to determine hours worked per task, which helped to further inform division of staff time across study service delivery types. The data collection spreadsheets also divided cost and effort information across time period (start up vs. implementation), resource category (capital vs. recurring), level of costs (i.e., costs specific to the intervention overall, each counselor, or each participant) and intervention booster delivery type (live call, SMS, IVR).