A simple regression of personal income per capita for the U.S. states is estimated from cross-section data for the years 1929, 1950, 1970 and 1990 with each state's distance from the equator as the regressor. While proximity to the equator is noted to have a sizable adverse effect on income,...

Using a good inequality index, and data on personal income and cost-of-living estimates for the period 1981-90, interstate inequality in 'nominal' and 'real' personal income per capita is compared. Four points are noted. First, inequality in real income is smaller than that in nominal income....

Five points are made in this study. First, using a well-recommended measure, inter-U3state income inequality is reported for each year from 1950 through 1989, and its very small magnitude is pointed out along with the U-shaped profiles. Second, it is shown that a simple quadratic-form model fits...