Leaver premium in Washington and comparison states

What this dataset measures

Built to check the claim, posted November 2, 2026 by the Yes on Initiative 645 campaign, that households leaving Washington since 2021 have earned more on average than households moving in. Six comparison states (neighbors, the biggest destinations and California) and all-state rankings test whether Washington's pattern is unusual.

Geography

Washington, Oregon, California, Idaho, Texas, Florida, Arizona, United States (all states, rankings)

Unit of observation

State and filing-year pair

Update cadence

Annual, when IRS publishes a new migration year

Curator

FactHub Research Team

Supporting files

Source snapshots, manifests, quality reports, documentation, and other materials used to produce or review this release.

• fh-analysis-results.json Documentation · application/json · 24.9 KB (25,481 bytes)

  Saved-analysis results written by the build script.

• fh-build-migration-dataset.js Transformation manifest · text/javascript · 8 KB (8,170 bytes)

  Node.js script that reads the IRS files and writes every table and result here.

Saved analyses

Sources

1. Internal Revenue Service, Statistics of Income (SOI): U.S. Population Migration Data Index of every migration year. State-to-state files used: https://www.irs.gov/pub/irs-soi/stateinflowYYYY.csv and stateoutflowYYYY.csv for YYYY = 1112 through 2223 (rows for each state's 'Total Migration-US' and for Washington's partner states).

   Retrieved November 3, 2026. Public domain (U.S. government work). Allowed; IRS data are U.S. government works.

   Reliability: Government. Built by IRS from address changes on the full population of individual income tax returns filed in two consecutive years. IRS has no stake in Washington's tax debate.

2. IRS SOI Tax Stats, Migration Data 2022-2023 Release page for the latest year, linking stateinflow2223.csv, stateoutflow2223.csv and the gross migration file 2223inmigall.csv.

   Retrieved November 3, 2026. Public domain (U.S. government work). Allowed.

   Reliability: Government. Official IRS release page. The 2023-24 files were not published as of November 3, 2026 (stateinflow2324.csv returned HTTP 404).

3. IRS SOI gross migration file by AGI class and age, 2022-2023 (2223inmigall.csv), and the same file for earlier years Inflow, outflow and matched returns by AGI class (agi_stub 7 = $200,000 or more) and by age of the primary taxpayer, with year-1 and year-2 AGI. Earlier years at https://www.irs.gov/pub/irs-soi/YYYYinmigall.csv for YYYY = 1112 through 2122.

   Retrieved November 3, 2026. Public domain (U.S. government work). Allowed.

   Reliability: Government. Same IRS return-matching as the state-to-state files, but excludes returns with negative AGI and includes moves abroad.

4. IRS, 2022-2023 Migration Data Users Guide Definitions: AGI is from the year-2 return and in thousands of dollars; 2022-23 matching change; disclosure rules; AGI classes and age groups in the gross file.

   Retrieved November 3, 2026. Public domain (U.S. government work). Allowed.

   Reliability: Government. IRS's own documentation of the files.

5. Revised Code of Washington 82.87.040, capital gains tax imposed Date the capital gains tax began: sales on or after January 1, 2022.

   Retrieved November 3, 2026. Public domain (Washington State law). Allowed.

   Reliability: Government. The official statute text published by the Washington Legislature's Code Reviser.

6. Engrossed Substitute Senate Bill 6346, Chapter 238, Laws of 2026 (session law) Washington's 9.9% tax on taxable income over $1 million: approved March 30, 2026; tax imposed beginning January 1, 2028.

   Retrieved November 3, 2026. Public domain (Washington State law). Allowed.

   Reliability: Government. The enrolled session law as published by the Washington Legislature.

Limitations and reproducibility

Reproducible from public sources: Every input is a published IRS SOI migration file (stateinflowYYYY.csv, stateoutflowYYYY.csv, YYYYinmigall.csv at https://www.irs.gov/pub/irs-soi/). The included script fh-build-migration-dataset.js reads those files and writes every table and saved-analysis result in this dataset.

• The latest IRS file is 2022-23: moves between the returns filed in 2022 and 2023, with income from tax year 2022. It cannot show any response to Washington's 2026 income tax, which applies from January 1, 2028.
• Covers only people who filed federal tax returns in both years and could be matched by taxpayer ID. Non-filers are left out.
• AGI comes from the second-year return, filed from the new address, so part of a mover's income may have been earned in the old state.
• Averages are pulled up by a few very high incomes and one-time gains, such as stock or home sales. IRS publishes no medians.
• IRS changed its matching method for 2022-23, adding about 5% more returns. 2014-15 return counts are unusually low in both directions.
• Interstate flows exclude moves abroad. The $200,000-plus counts come from IRS's gross migration file, which includes moves abroad and leaves out returns with negative AGI, so its totals differ slightly from the state-to-state files.
• The $200,000 class is a fixed dollar amount, so more filers cross it as incomes rise. It is far below the $1 million threshold of Washington's 2026 income tax, and IRS migration data have no $1 million class.