Methodology

The IRS builds this data from year-to-year address changes on individual income tax returns. A file labeled 2022 to 2023 compares the address on the 2022 return with the address on the 2023 return. It reports the number of returns filed (an approximation of households that moved), the number of personal exemptions (an approximation of individuals), and the total adjusted gross income (AGI) associated with those returns.

The data covers people who filed federal income tax returns. Non-filers, which include many lower-income and some elderly people, are not represented. Treat these counts as filer migration, not total population migration.

AGI is reported in thousands of nominal dollars and is not adjusted for inflation. We store it exactly as the IRS reports it and convert to dollars only for display, labeled nominal. Comparisons across years are nominal unless stated otherwise.

A common misreading is that the income of someone who moves is lost to the place they left. It usually is not: the job often stays and is refilled. We present net AGI as movement of filers and their reported income, nothing more. We do not frame it as economic gain or loss, and we make no claim about why anyone moved.

The data lags about two years behind the present. Two methodology breaks affect long comparisons: the series starting 2011 to 2012 used an improved approach, and the series starting 2022 to 2023 used an enhanced matching process. The 2022 to 2023 county file also adopted Connecticut’s nine planning regions in place of its legacy counties.

Genuine county-to-county and state-to-state flows are loaded from the IRS outflow files. Aggregate, total, and non-migrant rows are separated out and used for the headline totals. Every flow is validated against the official FIPS crosswalk, and rows that fail validation are quarantined and logged rather than loaded.

Headline inflow, outflow, and net figures use the IRS’s own “Total Migration, US and Foreign” totals, which include disclosure-suppressed small flows. The top origin and destination lists show only individual flows the IRS published above its disclosure threshold, so they will not sum to the headline total.

Source: IRS SOI Tax Stats, U.S. Population Migration Data. Public domain. Please attribute How America Moves when you cite figures from this site.