This paper describes the research that has been required to develop the factual evidence for challenges to inequitable school finance laws and for defenses of school finance reform legislation in Oregon and Wisconsin. Both the challenge to and the defense of school finance legislation use an analytical framework that focuses on the following fiscal characteristics of a state's school districts: school district property wealth, school tax effort, and school district expenditures. In the Oregon case the analysis demonstrates that disparities in expenditures and tax rates are related to differences in local property wealth. More specifically, it demonstrates that districts that have the largest amount of property wealth per pupil are able to spend more on education while exerting a low tax effort, whereas districts that are poor in property wealth are able to spend less while exerting an above-average tax effort. The analysis in the Wisconsin case demonstrates that the new law is inherently equitable, that property-poor districts have fared better under the new law than under the previous statute, and that property-poor districts would have benefited even more had the act been fully funded during the 1974-75 school year. (Author/IRT)