This study related tax rate and per pupil revenue to residential assessed valuation, percent residential of total assessed valuation, and selected socioeconomic independent variables for school districts in Cook, DeKalb, DuPage, Kane, and Lake counties in Illinois. Findings suggest that for homeowners and the students of these counties in 1976, the combination of high percent of residential property and low per pupil value of residential property shows high tax rates and low per pupil revenue; that school revenues in all high residential percent districts may be lower than revenues in low residential percent districts; and that the Illinois reward for effort is, in essence, a system of reward for districts with high percentage of residential valuation. Yet, while the present system helps homeowners, it does not produce combined state and local revenue that can keep up with inflation. The guaranteed yield is frozen at less than $1,300 combined state and local revenue per pupil, while other districts with higher local resources can increase the local revenue to produce a combined yield of several hundred dollars per pupil unit above the state guarantee. (Author/IRT)