This monograph uses the empirical relationship between income and years of school completed to examine differences in private economic incentives to invest in education among important segments of the population of the United States. Specifically, the relationship between income and education is examined as it is affected by race, sex, age, urban-rural residence, and region to determine the differences among these groupings, and the impact which these differences have on private incentives to invest in education. The data employed in this study are from the 1950 and 1960 Censuses of Population and represent estimates of the total population characteristics as derived from sample census data. The data relating income and education in the 1950 Census volumes represent estimates derived from a 3.3 percent sample of all census returns. The 1960 Census data were derived from either a 25 percent sample of housing units and persons in group quarters, or a 20 percent subsample of the original 25 percent sample schedules. It should be noted that the income estimates and/or rates of return derived from the cross-sectional census data do not reflect the secular growth of the economy or the increasing quality of education received. To this extent, the estimates developed in this study understate the worth of education. (Author/JM)