A 1973 Illinois school finance reform program initiated a guaranteed tax yield system that can also be considered a district power equalization system. This paper evaluates this reform according to four criteria: permissable variance, fiscal neutrality, reward for effort, and aid to urban areas. Emphasis is given to a discussion of legal and economic aspects of fiscal neutrality. The report includes limitations and qualifications of findings, but generally concludes that overall variation among districts has decreased, progress toward fiscal neutrality has been made, rewards for effort have increased, and large districts have received significant additional aid. Appended tables present the results and statistical methods. (DW)