The Census Bureau completed a full review of American Community Survey (ACS) disclosure avoidance (DA) methodology to ensure compliance with Department of Commerce Department Administrative Order, DAO 216-26, Disclosure Avoidance for Statistical Products, which eliminated the use of noise-based protections. The following updates have been made to the 2025 1-year tabulated data products to eliminate the use of noise-based DA methods: 

1. The use of household record swapping, a disclosure avoidance methodology in which a small percentage of household records are interchanged with a paired household in another geographic area, has been discontinued for ACS 1-year tabulated data products starting with the 2025 release. Prior to this change, household record swapping was applied during the production of internal 1-year microdata, that is used to produce tabulated data products and as input for creating 5-year internal microdata and the Public Use Microdata Sample (PUMS) files. Although swapping was applied during the 1-year microdata creation, it was designed to provide protection for small population areas (e.g., tracts, block groups) included in the 5-year data products, as well as individual records included in the PUMS files. While 1-year ACS data products were previously based on swapped data, the swapping was not instrumental for providing disclosure protections beyond what is afforded by the 65,000 population threshold for publishing the 1-year estimates, as well as the 20,000 population threshold for publishing the 1-year Supplemental Estimates. 
2.  The formal-privacy mechanism for 1-year unweighted sample counts in tables B98001, B98002, and B98003 and 1-year Supplemental Estimate unweighted sample counts in tables K209801 and K209803 has been replaced by rounded estimates. 

We used this opportunity to review all legacy ACS data release rules for tabulated data products with special attention to disclosure avoidance-focused rules. Many of the legacy rules were inherited from the 2000 Decennial Census Long Form (SF4) data products. The goal of the current review was to identify the origin and empirical justification for each rule to ensure a complete, high-quality product that is protected against disclosure as required by Title 13. Based on our review, the following updates have been made to the 2025 1-year data products to eliminate legacy rules lacking empirical support: 

1. Eliminated existing 500,000 geographic area population threshold for producing 1-year sub-population-based Selected Population Profiles and Subject Tables. This rule required at least 500,000 total population within a given geographic area, in addition to the 65,000 population threshold within the sub-population of interest, for producing a Selected Population Profile or Subject Table.  
2. Eliminated existing unweighted rule of 3 for aggregates, means, and ratios. This rule required at least 3 unweighted cases to be present for a given row for aggregate, mean, and ratio estimates to publish that estimate.  
3. Eliminated existing unweighted rule of 50 for non-residence geographies and sub-population tables. This rule required at least 50 unweighted cases to be present in the table universe for non-residence geographies (place of work, residence 1 year ago) or sub-population-based Selected Population Profiles and Subject Tables. 

Although the above rules have been eliminated, the 65,000 geographic area or sub-population threshold remains fully in place for 1-year data products, as does the 20,000 geographic area for 1-year Supplemental Estimates. These foundational population thresholds provide strong disclosure protection for 1-year data products and 1-year Supplemental Estimates. All legacy rules related to data quality also remain in effect to ensure the data meet ACS Program and Census Bureau statistical quality standards.  

For the 2025 1-year data release, the updated release rules described above resulted in the release of nearly 38,000 additional detailed tables, a 0.4 percent increase across all geographies and estimate types. This was driven especially by the increase in the number of tables reporting aggregate estimates (e.g., aggregate family income, aggregate gross rent, aggregate travel time to work), compared with the baseline for 2025 1-year if these changes were not implemented. Similarly, the 2025 1-year release included nearly 15,300 additional sub-population-based Selected Population Profiles and Subject Tables, a 3 percent increase, compared with the baseline for 2025 1-year.   

These changes allow the ACS 1-year tabulated data products to provide the most complete and high-quality data possible across all topics, geographies, and sub-populations while upholding our responsibility to protect respondent confidentiality under Title 13 of the U.S. Code.