The authors found that those born to parents in the bottom 20 percent of earners (measured by permanent income, or the average labor market earnings over people’s working lives) had a 39 percent chance of remaining in the bottom 20 percent. Those born in the bottom 20 percent of the wealth distribution had a 27 percent chance of staying there. On the other end of the spectrum, those born in the top 20 percent of permanent income and wealth distributions had a 41 and 47 percent chance of staying there, respectively. (Figures showing these transitions are available in The Regional Economist article “Which Persists More from Generation to Generation—Income or Wealth?”)
Residual income is the amount of net income generated in excess of the minimum rate of return. Residual income concepts have been used in a number of contexts, including as a measurement of internal corporate performance whereby a company's management team evaluates the return generated relative to the company's minimum required return. Alternatively, in personal finance, residual income is the level of income that an individual has after the deduction of all personal debts and expenses have been paid.