Fiscal data were analyzed for a nine-year period (1963-1971) for all school districts in Illinois. Two hypotheses were tested relative to two different definitions of equalization -- "permissible variance" and "fiscal neutrality." Support was given to the notion of increasing interdistrict equality relative to expenditures and tax effort. Support was also given to the hypothesis that grants-in-aid have done little to change the proportion of total funds available to the poorer students of the State. (Author)