For some topics, there are specific subject headings. For example, ERIC has a subject heading for Educational Equity (Finance). However, note that this search retrieves over 1600 hits--far more than is reasonable to go through. You can add addditional terms or you can apply different limits. Limiting to Reports, Research from 2000-2008 is just one way to potentially retrieve more relevant articles. Try different combinations-- combining SU Descriptor educational equity finance AND KE Identifier illinois is just one other possibility.
Some potentially relevant subject headings used in ERIC are POVERTY; DIVERSITY; EQUAL EDUCATION; STUDENT DIVERSITY; ECONOMICALLY DISADVANTAGED; EDUCATIONAL EQUITY (FINANCE); EDUCATIONAL FUNDING; EQUALIZATION AID; FUNDING FORMULAS; PROPERTY TAXES; SCHOOL DISTRICT WEALTH; SCHOOL TAXES; TAX ALLOCATION; TAX RATES
ERIC and Academic Search Premier
Remember that these two databases use different subject headings, so you will need to rely on key word searching.