If you came here looking for Colorado Health Access Survey (CHAS) data from 2021 or 2023 — or if you're already using data from those surveys in your work — we've got an update for you.
Following a review of statistical methodologies in November 2025, a slight change was made to population weights used in the CHAS. Many estimates are unchanged, and those that changed usually differ by only a fraction of a percentage point. As a result, some past estimates listed in this and other publications developed in 2025 and onward may vary slightly from previously published estimates, though these changes do not impact conclusions you might draw from the data (e.g. the 2021 statewide uninsured rate is now published as 6.7% rather than 6.6%).
If you arrived at this page because because you were trying to download materials from the 2021 or 2023 CHAS pages on our website, please visit the 2025 CHAS page for the most current materials. Workbooks, public use files, and other materials on that page contain data going back to 2009.
If you can't find what you're looking for, would like to confirm the accuracy of prior-year data you are already using, or have other questions, contact us: chas@coloradohealthinstitute.org.