The earnings gap between arrivals and leavers in Boulder County widened

Boulder County · Data as of 2026-10-24 · ALEX Intelligence

Read this carefully: Percentage points, not percent: the figure is the change in the gap, and the gap is itself a percentage. Only counties the IRS disclosed in both vintages, under the same FIPS code and above a minimum flow in each, are compared, because disclosure thresholds move between years and a flow that appears or vanishes at the margin is not evidence that anybody's behaviour changed. Connecticut is excluded throughout: its counties were replaced by planning regions, so no Connecticut geography is comparable across the change. The IRS withholds county-to-county flows below its disclosure threshold, so a county missing from this table is one whose flow was too small to publish, not one nobody moved from. Every total here is a total of disclosed flows and is therefore a floor.

Methodology

Source:

U.S. Internal Revenue Service, Statistics of Income Migration Data, county-to-county inflows, 2021-22 and 2022-23

Measure

Average income of arriving households, ranked highest first across every U.S. county the IRS recorded sending households to Boulder County (Boulder, Broomfield, CO) in both the 2021-22 and 2022-23 vintages (30 ranked in total).

How the headline figure is computed

The income gap between arriving and departing households was 11.0% in 2021-22 and 17.6% in 2022-23, both computed over only the counties the IRS disclosed in both directions in both vintages. The figure is the change in that gap, in percentage points.

Universe

Every U.S. county the IRS disclosed a flow with. Counties whose flow fell below the IRS disclosure threshold are absent from the source file altogether, so this ranking is of disclosed flows and its totals are a floor rather than a complete count of movers.

Vintage

2023

Reproduce this query

https://www.irs.gov/pub/irs-soi/countyinflow2223.csv https://www.irs.gov/pub/irs-soi/countyoutflow2223.csv https://www.irs.gov/pub/irs-soi/countyinflow2122.csv https://www.irs.gov/pub/irs-soi/countyoutflow2122.csv

Every figure on this page is computed directly from the dataset named above by ALEX Intelligence. No figure on this page was written by hand or by a language model. The query is stated so that anyone can re-run it and obtain the same table.