Demographics & Inequality: 2017 Edition

Every year, economist Mark Perry draws on Census Bureau reports to paint of picture of the demographics of inequality. Looking at 2017 data, he constructed the following table:


Once again, he concludes,

Household demographics, including the average number of earners per household and the marital status, age, and education of householders are all very highly correlated with household income. Specifically, high-income households have a greater average number of income-earners than households in lower-income quintiles, and individuals in high-income households are far more likely than individuals in low-income households to be well-educated, married, working full-time, and in their prime earning years. In contrast, individuals in lower-income households are far more likely than their counterparts in higher-income households to be less-educated, working part-time, either very young (under 35 years) or very old (over 65 years), and living in single-parent or single households.

The good news is that the key demographic factors that explain differences in household income are not fixed over our lifetimes and are largely under our control (e.g., staying in school and graduating, getting and staying married, working full-time, etc.), which means that individuals and households are not destined to remain in a single income quintile forever. Fortunately, studies that track people over time indicate that individuals and households move up and down the income quintiles over their lifetimes, as the key demographic variables highlighted above change, see related CD posts herehere and here.

… It’s highly likely that most of today’s high-income, college-educated, married individuals who are now in their peak earning years were in a lower-income quintile in their prior, single, younger years before they acquired education and job experience. It’s also likely that individuals in today’s top income quintiles will move back down to a lower income quintile in the future during their retirement years, which is just part of the natural lifetime cycle of moving up and down the income quintiles for most Americans. So when we hear the media and progressives talk about an “income inequality crisis” in America, we should keep in mind that basic household demographics go a long way towards explaining the differences in household income in the United States. And because the key income-determining demographic variables are largely under our control and change dynamically over our lifetimes, income mobility and the American dream are still “alive and well” in the US.

Elsewhere, he reveals some rather good news from the same report:

These are his key takeaways:

  • The 1.8% gain in real median US household income last year brought median income to more than $61,000, the highest level ever recorded.
  • The income gain in 2017 was the fifth annual increase and the first period of five consecutive increases in median household income since the late 1990s.
  • Compared to 1975, the typical US household today has $12,464 more annual income (in 2017 dollars) or more than $1,000 more per month in real, inflation-adjusted dollars to spend on goods and services, many of which have become much more affordable today than in the 1970s (or weren’t even available then).
  • Adjusted for household size, which has been falling over time, real median household income per household member last year of $24,160 (in 2017 dollars) was the highest in history.
  • Real median income for married couples with both spouses working reached a new all-time record high last year of $111,000 and has more than doubled from $54,700 in 1963.
  • By three different measures — income shares of the top 5% and 20% and the Gini coefficient — there is no evidence of a significant rise in income inequality over the last 25 years; all three measures have been remarkably flat for more than two decades.
  • The share of US households with incomes of $100,000 or more (in 2017 dollars) reached a new record high of 29.2% last year, which is more than triple the share of households in 1967 with that level of income. At the same time, the share of US low-income households (real incomes of $35,000 or below) fell to a near-record low of 29.5%.
  • America’s middle-class is disappearing but into higher, not lower, income categories over time.