Are procured quantities of implants adequate and appropriate? Modeling procurement, inventory, and consumption of contraceptive implants during rapid uptake

Abstract

Donors and others are concerned that implants procured under the Family Planning 2020 Initiative exceed the number sought by clients, resulting in accumulating stocks. To explore this issue, we examined 3 questions across 9 countries: (1) How accurate were procurement quantities given requirements for filling supply chains for the rapidly growing implant programs? (2) Is there a standard factor that can be applied to consumption data to predict procurement volumes required? (3) How accurately do demographic estimates mirror dispensed-to-client data? We created a model incorporating public-sector supply chain system parameters to calculate system "imputed" inventory and the system "filled-to-max" inventory. Comparing results determined the adequacy of the procurement quantities. The proportion of consumption that the filled-to-max inventory represented through time suggests whether a standard factor can be applied to consumption to predict necessary procurement volumes. We compared demographic estimates to consumption data to determine the usability of the former in predicting demand. According to model results, 3 of the 9 countries came close to procuring accurate quantities over the study period between 2010 and 2017, 4 had procurement volumes lower than what was required to fill the supply chain to maximum inventory requirement levels, and 2 had volumes that exceeded the need. We found no standard factor for relating inventory quantities to consumption rates across countries, given that inventory needs can vary based on system design parameters and the rates of growth or decline in consumption. Finally, we observed that our demographic estimates were on average lower than the dispensed-to-client data in the 6 countries for which these data were available. Study results show that the significant investments in procurement quantities for the rapidly growing implant programs were justified based on consumption and system design. This research should assure observers that rapid increases in implant procurement quantities (where data are available) have generally not resulted in overstocks of the system to date. It suggests that the relationship between procurement quantities and consumption levels cannot be accurately assessed without understanding the country supply chain, inventory control parameters, and current and future demand.