This paper evaluates the equity dimensions of a grant-in-aid system based on the Resource Cost Model (RCM), as proposed by the Illinois State Board of Education. The first section is an independent evaluation of the conceptual and legal aspects of the RCM, focusing on both the weaknesses and the strengths of the model. In the second section, an initial empirical investigation of the RMC distribution is described. The third section addresses the central purpose of the study: the conduct of the equity tests. In addition, reasons are provided for the abandonment of the older dispersion tests as not appropriate with the RCM model. In the fourth section, contrasts are drawn between the RCM and other reform proposals currently within the Illinois General Assembly. The conclusion suggests that if the RCM were funded at the levels indicated by the board's proposal, progress would be made toward equity goals. Nine illustrative tables are provided to complement the text, and an appendix offers the rationale for the reforms, as cited by the Governor of Illinois and the State Superintendent of Education respectively. (TE)