In spite of 1983 legislation intended to equalize financial differences among school districts, Pennsylvania continues to experience inequalities in school funding. A study of Pennsylvania school finance over a 10-year period, 1984-85 through 1993-94, examined differences in spending among the 25 lowest spending districts (Lo-25) and the 25 highest spending districts (Hi-25) in relation to their location, size, wealth, revenue sources, and effort. The Lo-25 districts were all small towns and rural areas. The Hi-25 were suburban districts near the two largest urban centers and urban districts in Pittsburgh. The difference in spending between the Lo-25 and the Hi-25 remained at a 2:1 ratio over the 10-year period. The differences in wealth per student between the two groups increased, such that in 1993-94 the Hi-25 had over four times as much wealth per student as the Lo-25. In 9 of the 10 years, the Hi-25 equaled or surpassed the Lo-25 in their local tax effort. The Hi-25 received more federal revenue per student in each of the 10 years. Since the Pennsylvania constitution requires the state to provide "a thorough and efficient system of public education" to its children regardless of where they reside, the state will have to increase appropriations or reallocate existing funds to low spending districts. Contains references and data tables on expenditure, wealth, and effort ratios between high and low expenditure districts and on ratios for general fund revenue per Average Daily Membership (ADM) between high and low expenditure districts. (Contains 10 references.) (TD)