Allocation of Shared Costs
We allocated shared costs based on their use for activities related to each intervention arm versus use for other activities, such as research activities related to the RCT, and removed all non-intervention costs. We divided counselor costs based on the relative time required to conduct the in-person counseling sessions and live booster calls. All other costs were divided based on effort allocation across study booster delivery types, in keeping with standard costing practices. We separated total observed costs into start up and implementation costs.