A report from the School Choice Demonstration Project examines issues concerning the funding formula used for the Milwaukee Parental Choice Program (MPCP). It finds that the program generates a net saving to taxpayers in Wisconsin but imposes a significant fiscal burden on taxpayers in Milwaukee. However, these findings depend significantly on how many students would have attended public school if the voucher option were not available, as well as on the actual resource requirements for those new voucher users. The report ignores the second assumption. It considers the first, although its key findings about the existence and magnitude of any savings and burdens are nonetheless dependent on that assumption. The issues raised by this report highlight some ways in which voucher policies are complex to design and implement and must be carefully evaluated on both efficiency and equity grounds.