What is real data, and what is a what-if
Real data. Every year from 2000 to 2024 uses that year’s published BLS Consumer Expenditure Survey table, which ranks U.S. households into five income groups (quintiles). From it come income before and after taxes, the income cut-offs between groups, household size, spending on six categories (including education), and benefit income. For the five quintiles, the model reproduces BLS’s averages exactly.
What-ifs. Anything finer than quintiles (deciles, the top 1%, custom splits) is estimated from a smooth income curve inside each quintile. Childcare, benefit amounts other than 100%, expense edits, the minimum tax, investing and the wealth taxes in Fig. 3 are scenarios you control. Fig. 3’s net worth itself is measured data from the Federal Reserve.
Breaks in the dataBefore 2004, BLS income figures cover only households that fully reported their income; from 2004 BLS fills in missing income. From 2013, BLS estimates taxes with a tax model instead of asking households, which is why BLS after-tax income for the top group dips that year. By default this site uses CBO’s consistent federal income tax rates instead, so the dip disappears. To compare, turn on “After tax” and choose a method under Advanced. BLS doesn’t publish the top group’s 2023 public assistance figure, so 2022’s is used. BLS also published no after-tax income for 2024, because it didn’t update its tax model that year; the BLS-based tax methods use each group’s 2023 tax rate for 2024.
Projections · 2025–2026BLS hasn’t published household data for these years yet. They start from 2024 and grow every income and cost with consumer prices (CPI-U), so they show what happens if everything simply kept pace with inflation. The 2025 price average covers 11 months because BLS published no October 2025 index; 2026 covers January–August. The 2026 S&P 500 return is year to date through September 14. Projected years are shaded and dashed.
Known limitationsBLS’s Consumer Expenditure Survey is known to under-report income compared with national accounts, and low-income households often report spending more than their income (through savings, debt, family help or unreported income). Figures are group averages, not medians, and each income group mixes ages and household types, including retirees and students. Per-person amounts use a simple headcount, and CBO rates cover federal income tax only. Treat the results as rough, comparative illustrations. Groups are snapshots, not the same people over time. Each year’s lowest 20% is whoever ranks lowest that year, and households move between groups as they age, change jobs, retire or change household size. Studies that follow the same people find real movement between groups over a decade, but also strong persistence from one generation to the next, so the gaps here describe positions in the distribution, not a fixed set of households.
An outside checkThe Federal Reserve’s survey of household economic well-being found that 63% of U.S. adults would cover a $400 emergency expense with cash or its equivalent in 2024 (the same as in 2023), leaving more than a third who couldn’t. That fits this site’s finding that lower-income groups have little or nothing left after essentials, though the survey measures adults, not households, and savings as well as income.