Effect of B on the ratio of total costs when accounting vs. not accounting. Legend: R
(the ratio of distribution costs between a campaign which accounts for LLINs and one that does not) vs. R
(the ratio of total per LLIN costs of a campaign that accounts for nets compared to one that does not) as B (the proportion of the per LLIN costs of the campaign which does not account for existing nets which is due to the commodity cost of the LLIN itself) is varied from 40% of the total costs for a blanket campaign to 80%. The lightest red line corresponds to B = 40% while the middle line corresponds to B = 60% and the darkest line corresponds to B = 80%. Arrows indicate how to read the relationship between a doubling of R
and the effect of R
for a level of B = 60%.