This study seeks to provide outcomes-based information on Oklahoma's proposal to give tax credits for contributing to organizations that provide scholarships to K-12 private schools. The study constructs a model to determine the fiscal impact of tax-credit scholarships on the state and on local school districts. The author estimates the impact that tax-credit funded tuition scholarships will have on the distribution of students between Oklahoma's public and private schools by estimating the number of students transferring from public to private schools in response to different scholarship values. He uses these estimates to construct a model to determine the impact that scholarship tax credits will have on state education aid to school districts and to calculate the "break-even" rate of program participation. The program's break-even rate is the number of public school students that would have to transfer from public to private schools in response to the scholarship program in order to make the tax credits fiscally neutral from the perspective of Oklahoma state government. He uses district-level expenditure and enrollment data to estimate the percentage of expenditures that vary with changes in enrollment levels across school districts in Oklahoma. He then compares the revenue and expenditure impacts of scholarship tax credits on school districts to determine their net impact on school district finances. Key findings for this study are presented. (Contains 11 tables, 10 figures and 23 notes.)