I’m reposting economist Mark J. Perry’s entire post because it is so excellent.
Much is made of “income inequality”. Perry focuses on the demographic differences between upper income and lower income groups.
These are correlations, not necessarily causations, but the questions remain.
Click to enlarge the table.
Here’s the bottom line: stay in school and graduate; get a degree; get married and have kids (in that order); work hard and get a full time job.
Most of these are completely within our control.
The Census Bureau released its annual report yesterday on “Income and Poverty in the United States” with lots of newly updated data on household income and household demographics. Based on those new data, I present my annual post titled “Explaining Income Inequality by Household Demographics” (see my previous versions of this analysis for years 2013, 2014, 2015 and 2016).
Most of the discussion on income inequality focuses on the relative differences over time between low-income and high-income American households. But it’s also informative to analyze the demographic differences among income groups at a given point in time to answer questions like:
- How are high-income households different demographically from low-income households that would help us better understand income inequality?
- For low-income households today who aspire to become higher-income households in the future, what lifestyle and demographic changes might facilitate the path to a higher income?
The chart above shows some key demographic characteristics of US households by income quintiles (five equal groups of US households) for 2017, using Census Bureau available here and here. Below is a summary of some of the key demographic differences between American households in different income quintiles in 2017:
1. Mean number of earners per household. On average, there are significantly more income earners per household in the top income quintile households (2.06) than earners per household in the lowest-income households (0.41). It can also be seen that the average number of earners increases for each higher income quintile, demonstrating that one of the main factors in explaining differences in income among US households is the number of earners per household. Also, the unadjusted ratio of average income for the highest to the lowest quintile of 18.0 times ($221,846 to $12,319), falls to a ratio of only 3.6 times when comparing “income per earner” of those two quintiles: $107,692 for the top fifth to $30,046 for the bottom fifth.
2. Share of households with no earners. More than 63% of American households in the bottom fifth of households by income had no earners for the entire year in 2017. In contrast, only 4.3% of the households in the top fifth had no earners last year, providing more evidence of the strong relationship between household income and income earners per household.
3. Marital status of householders. Married-couple households represent a much greater share of the top income quintile (76.1%) than for the bottom income quintile (17.1%), and single-parent or single households represented a much greater share of the bottom one-fifth of households (82.9%) than for the top one-fifth (23.9%). Consistent with the pattern for the average number of earners per household, the share of married-couple households also increases for each higher income quintile, from 17.1% (lowest quintile) to 35.3% (second lowest quintile) to 48.1% (middle quintile) to 63.5% (second highest quintile) to 76.1% (highest quintile).
4. Age of householders. About 7 out of every 10 households (69.4%) in the top income quintile included individuals in their prime earning years between the ages of 35-64, compared to fewer than half (41.1%) of household members in the bottom income quintile who were in that prime earning age group last year. The share of householders in the prime earning age group of 35-64 year-olds increases with each higher income quintile, from 41.1% (lowest quintile) to 43.9% to 52.0% (middle quintile) to 60.6% to 69.4% (highest quintile). Compared to members of the top income quintile of households by income, household members in the bottom income quintile were more likely (19.5% for the lowest quintile vs. 15.0% for the highest quintile) to be in the youngest age group (under 35 years), and more than twice as likely (39.4% vs. 15.6%) to be in the oldest age group (65 years and over).
By average age, the highest three income groups are the youngest (about 50 years on average) and the lowest income group is the oldest quintile on average (56 years).
5. Work status of householders. More than four times as many top quintile households included at least one adult who was working full-time in 2017 (77.4%) compared to the bottom income quintile (only 18.4%), and five times as many households in the bottom quintile included adults who did not work at all (68.5%) compared to top quintile households whose family members did not work (13.2%). The share of householders working full-time increases at each higher income quintile (18.4% to 47.1% to 61.2% to 71.0% to 77.4%).
6. Education of householders. Family members of households in the top fifth by income were 4.2 times more likely to have a college degree (65.4%) than members of households in the bottom income quintile (only 15.4%). In contrast, householders in the lowest income quintile were 11.3 times more likely than those in the top income quintile to have less than a high school degree in 2017 (21.5% vs. 1.1%). As expected, the Census data show that there is a significantly positive relationship between education and income.
Bottom Line: 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 CDposts here, here and here. And Thomas Sowell pointed out in one of his syndicated columns in March 2013 “Economic Mobility” that:
Most working Americans who were initially in the bottom 20% of income-earners, rise out of that bottom 20%. More of them end up in the top 20% than remain in the bottom 20%. People who were initially in the bottom 20% in income have had the highest rate of increase in their incomes, while those who were initially in the top 20% have had the lowest. This is the direct opposite of the pattern found when following income brackets over time, rather than following individual people.