During the last decade the search for a school finance system that reduces or eliminates the relationship between per pupil revenues for education and per pupil local property wealth has received special attention, in part due to the intervention of the judicial system.1 While the aims of the school finance reforms that took place during the 1970s are numerous, a recent review of these reforms characterizes the attention paid to low-wealth school districts as the key feature (Odden, 1978). Furthermore, the National Center for Education Statistics has been mandated by Congress to calculate state equity profiles that include an assessment of the relationship between educational revenues and wealth. Despite the focus on the relationship between revenues and local wealth, a single agreed-upon definition of this relationship has not emerged. In order to specify the particular group of definitions that is examined in this article, two distinctions need to be highlighted. First, the relationship between revenues and wealth can be formulated as either an ex post or ex ante concept (Barro, 1974; Feldstein, 1975; Friedman, 1977; Friedman & Wiseman, 1978; Gatti, Tashman, & Sweet, 1978; Berne & Stiefel, 1979). Ex post conceptions of the relationship are based on the actual patterns of revenues and local wealth that prevail in the school districts concerned. These actual patterns can be observed only after each district responds to the school finance plan and thus makes its spending decisions. Ex ante conceptions are based on the characteristics of a school finance plan rather than the actual spending that results from the plan. For example, the notion of yield for equal effort is a popular ex ante conception that can be assessed by examining a school finance plan without regard for the actual spending levels that each district chooses. While the measurement issues surrounding both ex post and ex ante conceptions deserve attention, this paper is more modest in its aims and will concentrate solely on ex post conceptions. A second distinction can be drawn to further specify the definitions of the ex post relationship to be examined in this article. This distinction revolves around the following question: Can the assessRobert Berne and Leanna Stiefel are Associate Professors of Public Administration and Economics, respectively, at the Graduate School of Public Administration, New York University. They contributed equally to the article and the names are listed alp abetically, by convention. Funds were provided by the Ford Foundation. We would like to thank Peter Stowe and several anonymous referees for their helpful comments on this paper, Chris Hakusa for his computer programming assistance, and Karen Gruhn for her secretarial assistance.