Sustainability has been a core principle of the BID Initiative from its earliest days. In order to budget for, fund, and sustain data quality and data use interventions, and to scale them nationwide in Tanzania and Zambia, countries must understandthe upfront and recurrent costs associated with implementing these interventions. As part of the economic evaluation of the BID Initiative, BID is estimating the Total Cost of Ownership (TCO) of data quality and data use interventions in three regions of Tanzania (Arusha, Kilimanjaro, and Tanga) and one region in Zambia (Southern Province). The TCO tool provides a financial estimate of the total investment for the BID Initiative in each region, and it includes the upfront costs to design data quality and data use interventions, the costs to implement and deploy them, and the recurrent costs to sustain them over three years.