Dear IPUMS User,

I know many of you have been following developments in Census 2020 and the proposed citizenship questions. Several sessions at the Population Association of America (PAA) covered many aspects of Census 2020 planning and were well-attended with lively discussions. I’m writing to you today about plans for the American Community Survey (ACS). Please join me in asking the Census Bureau to clarify their plans for ACS disclosure avoidance control and dissemination. We want to protect the usability of the important public use data that we all use in our work. 

Here's the short version: please sign our open letter to the Census Bureau asking for transparency in changes to the ACS. For the long version, please keep reading and visit our webpage on this topic.

The Census Bureau is planning an extensive revision of procedures for ensuring the confidentiality of public use data, based on a method known as "differential privacy." The new disclosure avoidance system will rely on injecting noise into the data, and the new procedures may reduce or even eliminate the usability of public use data for many common research and policy applications. For more information, see our recent working paper and forthcoming article.

The American Community Survey (ACS) is the single most important statistical source in the social sciences. They generate 9,000 articles a year, and a new paper appears about every hour. If these data become unusable, unreliable or available only through restricted-access environments because of the new confidentiality measures, that would have profound consequences across many areas of demographic, economic, and policy research.

Acknowledging the importance of the ACS data, we are seeking clarification and engagement with the research community from the Census Bureau. Our open letter requests:

1. A public timeline for changes to the ACS summary files and microdata.
2. Engagement with the research community in advance of any changes.
3. Public versions of new noise-infused ACS summary files and microdata for 2005-2017 so that researchers can assess their usefulness by replicating existing studies.

If you support these requests, please sign our letter.

Thank you,

Steven Ruggles
IPUMS Director
Regents Professor of History and Population Studies