Summary:

The American Community Survey (ACS) 1-year estimates for 2025 have been released today, October 29, 2026. The ACS 1-year estimates include demographic, social, and economic data about people and households, reported for geographic areas with at least 65,000 residents (or 20,000 residents for a small set of Supplemental Tables).

These estimates are the first ACS data release following the Census Bureau’s implementation of a new disclosure avoidance policy that stands to impact data granularity (how much detail can be published), data privacy, or both. Ensuring compliance with this new policy led to a delay in this release (in the past three years, these estimates were released in the first two weeks of September).

We reviewed a sample of the newly released tables with smaller cell sizes and found no conclusive evidence of systematic changes or reduction in data availability from the tables analyzed, compared to the data available in these tables from the past four years of ACS 1-year data releases (2021 through 2024).

What is disclosure avoidance?

Disclosure avoidance is meant to protect the people in the data. According to the Census Bureau, it is “efforts made to reduce the risk of disclosing confidential or otherwise protected information about individuals, businesses, or other organizations represented in statistics.”

Accidental disclosure can be a risk, especially when there are very small numbers in published data tables. For example, if only one Asian woman over age 75 lived in a Census tract, published data could reveal her poverty status to anyone who knew who lives there.

A variety of methods have historically been implemented and considered to avoid disclosing sensitive information while still providing detailed and accurate data, including data swapping, rounding, top-coding (capping medians and means at a lower or upper bound), suppression, and – beginning with the 2020 Decennial Census – a formal privacy protection algorithm called differential privacy that infused small amounts of noise into the data.

What is changing?

The Department of Commerce’s Department Administrative Order (DAO) 216-26, released in June 2026, changes the methods that can be used for Disclosure Avoidance. Specifically, it:

Prohibits noise infusion: Many previous Census releases have employed noise infusion: introducing small random changes to data values. This meant that specific values were sometimes altered by a small amount, but in a random and neutral way that still resulted in accurate geographic summary data. A form of noise infusion, data swapping, has historically been the primary tool the Bureau has used to protect data in ACS tables. The DAO states this technique “shall not be used” moving forward.
Requires relying solely on coarsening and suppression: The DAO allows only for coarsening, which reduces the detail of data, and suppression, which is the withholding of data from publication. Per the Census Bureau, coarsening is the preferred disclosure avoidance method, while suppression should only be used as a “last resort.”

Our concerns about these changes

These changes increase the potential for more suppressed and less granular data in statistical products from the Census Bureau, leading to less information about smaller geographies and their respective populations. Moreover, there is a potential for reduced privacy protections in Census Bureau data.

For the 2020 Decennial Census, the Census Bureau had implemented a formal privacy protection method called differential privacy to protect against the growing risk of data re-identification arising from the increase in commercially available data on people and households and advances in computing technology. Differential privacy offers the strongest data privacy protections but is not allowed by the current policy directive on disclosure avoidance.

Although differential privacy was not being used for the ACS data, the Census Bureau had been actively researching other approaches to improve ACS data privacy protections, including the use of synthetic microdata which is also now disallowed.

Data granularity and accuracy are balanced against privacy protection – either one or the other could be weakened depending on how the Census Bureau weighs these competing concerns as they implement the new disclosure avoidance policy.

CTData’s initial investigation into the new release

The Census Bureau stated in a prerelease webinar that these changes should not result in any decrease in the number of tables, geographic levels, or data granularity availability in the 2025 ACS 1-year estimates since these estimates are only released for geographic areas with populations of 65,000 or more (or 20,000 for the Supplemental Tables).

Staff at CTData reviewed a sample of the newly released tables with smaller cell sizes to confirm the data seems as complete as previous years (please see the full list of tables in the Notes section). We found no conclusive evidence of systematic changes or reduction in data availability from the tables analyzed, compared to the data available in these tables from the past four years of ACS 1-year data releases (2021 through 2024).

The availability of data in some Supplemental Tables for some smaller Connecticut towns varied across years, but there was not a clear trend for lower data availability in the 2025 estimates. Variation in data availability across years could be due to changes in the town’s population size, the ACS survey sample size, or ACS survey data quality for that town in that year. However, this was not a comprehensive review of all 2025 ACS 1-year estimates tables.

Looking ahead:

While we were not surprised to see little change in the 1-year estimates, we look to the 2025 ACS 5-year estimates, which do not yet have a confirmed publication date, with greater concern. Because these tables involve more granular geographic areas than the 1-year estimates, changes to the disclosure avoidance policy may have a larger impact on these 5-year estimates. The policy may also have a greater impact on the ACS public-use microdata, which allows data users to create custom tabulations from a subsample of the ACS data.

We will be providing an in-depth analysis of whether or how the new privacy protections impact the 5-year estimates when they are released.

In an August 2026 Census Bureau blog post on the new disclosure avoidance policy, George M. Cook, performing the duties of the U.S. Census Bureau Director, wrote that they are “researching new disclosure avoidance methods [for the ACS]. Transitioning to methods compliant with the new order will occur gradually, with a full transition by 2029.” Therefore, ACS disclosure avoidance approaches and any resulting data availability or privacy impacts may continue to evolve over the next several years.

Notes:

Below is the list of tables we examined, comparing the new 2025 ACS 1-year release to four previous 1-year ACS releases (2021-2024) for completeness.

For More Information

As the Connecticut Census State Data Center, we will continue to stay on top of census news and share it as it becomes available. You can bookmark our blog or get updates by subscribing to our newsletter and following us on Facebook, and LinkedIn, and Instagram. To learn more about the Census and resources provided by CTData, head to our Census Data Porta l. Explore other data sets and analyses at data by topic and data projects. Join us for our conference to connect with other data users or learn some new data skills at our workshops.

The Census Bureau Has Implemented a New Disclosure Avoidance Policy for the Newly-Released 2025 ACS 1-Year Estimates: Did the Policy Change Impact the Data?