The purpose of this study was to assess the merit of using personal income in the determination of a school district's fiscal capacity for the apportionment of New York state aid. Both personal income and full valuation of real property suffer from technical weaknesses, but improvements in the data are possible if the state is willing to underwrite the cost. Calculations replacing full value of real property with 1970 personal income data produced several changes in state aid allocation. The state's five poorest districts, five big cities, and other central cities would experience a drop in formula aid. Conversely, the five wealthiest school districts with pupil populations over 500 and the suburban areas would receive less aid. If 1976 New York State taxable income is used instead of 1976 full valuation as the wealth measure, similar shifts occur. Because of limitations with the census data, findings are suggestive, not definitive. Personal income will not be acceptable as a total substitute for full valuation as the measure of a school district's wealth. Before personal income is used in a composite wealth index for the apportionment of aid, viable combinations need to be examined within several alternative formula options. (Author/JM)