Data source explanation
What is the World Inequality Database?
The World Inequality Database, often called WID, provides data on income and wealth inequality across countries and over time.
For the Wealth Reform Project, this source is useful because it allows the United States to be compared with other countries instead of being studied in isolation.
Why it matters
Wealth concentration can look normal if a country only compares itself to its own recent history. International data helps ask a broader question: are high levels of inequality unavoidable, or do different policy systems produce different outcomes?
Comparing countries can help show whether tax systems, labor rules, housing markets, public services, inheritance patterns, and ownership structures are associated with different levels of income and wealth concentration.
Useful categories
| Category | Examples | Why It Matters |
|---|---|---|
| Income shares | Top 1 percent, top 10 percent, bottom 50 percent | Shows how national income is divided among different groups. |
| Wealth shares | Top wealth groups, middle groups, lower-wealth groups | Shows ownership concentration across households. |
| Country comparisons | United States compared with Europe, Canada, Japan, and other regions | Shows whether inequality patterns differ across policy systems. |
| Historical trends | Inequality over decades | Shows whether concentration is rising, falling, or changing slowly. |
| Pre-tax and post-tax comparisons | Income before and after taxes and transfers | Helps evaluate how public policy changes inequality outcomes. |
How this source will be used
WID data can help place U.S. wealth reform debates in international context. Instead of asking only whether inequality exists, the project can ask how U.S. patterns compare with other wealthy countries.
The data may also help identify which kinds of policy systems are associated with broader ownership, lower income concentration, or stronger household security.
Possible first charts
- Top 1 percent income share in the United States compared with selected countries.
- Top 10 percent wealth share across countries.
- Bottom 50 percent income or wealth share over time.
- Pre-tax versus post-tax inequality comparisons.
- Long-term inequality trends in the United States.
Connection to proposals
International inequality data can help evaluate whether a reform idea is unrealistic or whether similar systems already exist elsewhere.
This does not mean another country’s policy can simply be copied. Different countries have different laws, cultures, economies, and institutions. But comparison can reveal useful possibilities and warnings.
Current project status
The World Inequality Database has been identified as an important comparison source. The next step is to review available downloads, select a small group of country comparisons, and decide which inequality measures are easiest to explain to the public.