Why the Census Bureau Adopted Differential Privacy for the 2020 Census of Population


In September 2017, the Census Bureau announced, at a meeting of its Scientific Advisory Committee, that the test products from the 2018 End-to-End Census Test would be protected using differential privacy. The 2018 E2E test is the prototype of the full 2020 Census production system. Hence, unless the differential privacy system used for the 2018 E2E test fails, the expectation is that the full set of publication products from the 2020 Census will be protected by differential privacy. Importantly, the Bureau also indicated that the engineers implementing the 2018 E2E Test system and the 2020 Census production system would not be allowed to choose the privacy-loss budget, or make other decisions related to the allocation of that budget to different components of the privacy protection system. The decisions regarding the privacy-loss budget will be made by the Data Stewardship Executive Policy Committee (DSEP). This design ensures that the senior executive staff, and not the system engineers, will select the point on the privacy-loss, publication accuracy frontier that balances the dual mandates to produce data that are suitable for their intended uses and protective of the confidentiality of the respondents’ information.


John M. Abowd is Associate Director for Research and Methodology and Chief Scientist at the Census Bureau and the Edmund Ezra Day Professor of Economics, Professor of Statistics and Information Science at Cornell University. He is also Research Associate at the National Bureau of Economic Research (on leave while serving in the federal government), Research Affiliate at the Centre de Recherche en Economie et Statistique (CREST, Paris, France), Research Fellow at the Institute for Labor Economics (IZA, Bonn, Germany), and Research Fellow at IAB (Institut für Arbeitsmarkt-und Berufsforschung, Nürnberg, Germany). He is the past President (2014-2015) and Fellow of the Society of Labor Economists; past Chair (2013) of the Business and Economic Statistics Section and Fellow of the American Statistical Association; elected member of the International Statistical Institute; and a fellow of the Econometric Society. He has served as Distinguished Senior Research Fellow at the United States Census Bureau (1998-2016) and on the National Academies’ Committee on National Statistics (2010-2016). He currently serves on the American Economic Association’s Committee on Economic Statistics (2013-2018). He was the Director of the Cornell Institute for Social and Economic Research (CISER) from 1999 to 2007. His current research focuses on the creation, dissemination, privacy protection, and use of linked, longitudinal data on employees and employers.