The "Elementary and Secondary Education Act of 1965" ("ESEA") requires that school districts provide services to higher-poverty, Title I schools, from state and local funds, that are at least comparable to services in lower-poverty, non-Title I schools. The current Title I comparability requirement allows school districts to demonstrate compliance in various ways and does not require comparability of actual school-level expenditures. New data collected in response to a requirement in the "American Recovery and Reinvestment Act of 2009" ("ARRA") make it possible, for the first time, to conduct a nation-wide analysis comparing school-level expenditures in Title I and non-Title I schools and to examine the potential impact of revising the Title I comparability requirement to focus on school-level expenditures. This policy brief examines the projected number of school districts that would be out of compliance with an expenditures-based comparability requirement under various possible specifications, the amount of funds that such districts might need to add to Title I schools and higher-poverty schools in order to come into compliance, and the amount of additional funds that could flow to low-expenditure schools. Appended are: (1) Data Source and Quality; and (2) Supplemental Tables. (Contains 7 tables and 6 footnotes.)