This report examines the meaning and utility of several different desegregation-related measures relevant to Federal policy and technical assistance. Following the introduction, Section II discusses alternative measures of school segregation and desegregation. Major indices are compared, using a hypothetical school district for illustrative calculations. This comparison is extended to show the effects of modifying school racial composition in various ways, and observations are offered about commonly-used measures of school segregation. Section III examines the reduction of racial isolation measures used to determine the allocation of Emergency School Aid Act funds, and offers an alternative that can further decrease bias against districts with large minority populations by correcting for changes in a district's overall racial composition. An addendum to the section presents a comparison of three indices for measuring the severity of racial isolation. The final section offers a simple model for considering the costs and benefits of desegregation over time, in terms of "white flight" or resegregation. (CMG)