The migration dataset shows domestic taxpayer migration among all states, MSAs, and counties in the United States. The data goes back to 2012 (2012 tracks migration from 2011-2012) and is updated by Lightcast as it is released by the IRS. IRS migration data generally lags by 2 years.
The IRS migration dataset does not represent the entire population, but rather is a good indicator of the number of migrating workers within the labor force, based on taxpayer counts. Specifically, the following demographics are under-represented:
Youth (not required to file taxes)
Elderly (not required to file taxes)
The poor (not required to file taxes)
The very wealthy (not required to file taxes)
New filers (excluded because they did not file the previous year)
Former filers (excluded because they filed in the previous year but not the current year)
Some joint filers (only the primary taxpayer is included)
Mistakes (errors on a tax return can cause it to be excluded)
Lightcast migration data is based on individuals, as reported by the IRS, rather than the number of returns. On recommendation from the migration expert at the IRS, Lightcast multiplies the published number of migrations by 0.9 to better approximate the actual number of taxpayers that are moving. Their recommendation is based on the assumption that 90% of exemptions claimed on tax returns actually represent a person, while the remaining 10% do not.To read more about the IRS's migration data, visit the IRS's page.