Director John Abowd to speak at ILR

Tuesday, January 30, 2018

Tuesday, February 6, 4:00 - John Abowd, Associate Director for Research and Methodology and Chief Scientist, U.S. Census BureauEdmund Ezra Day Professor of Economics, Professor of Statistics and Information Science, and the Director of the Labor Dynamics Institute (LDI), will speak on "Staring Down the Database Reconstruction Theorem with Applications to the U.S. Census Bureau."

For national statistical agencies, the Big Bang event happened in 2003 when Irit Dinur and Kobbi Nissim directed the attention of cryptographers to safe systems for data publication from confidential sources. And the initial message was a very strong result showing that most of the confidentiality protection systems used by statistical agencies around the world, collectively known as statistical disclosure limitation, cannot defend against a database reconstruction attack. Such an attack recreates increasingly accurate record-level images of the confidential data as an agency publishes additional accurate statistics from the same database. Why are we still talking about this theorem fifteen years hence? What is required to modernize our disclosure limitation systems? The answer is recognizing that the database reconstruction theorem identified a real constraint on agency publication systems—there is only a finite amount of information in any confidential database. Statistical agencies can’t repeal that constraint. But acknowledging the constraint doesn’t help with other half of the dual mandate: the public-good mission to publish data that are suitable for their intended uses. The hard work is incorporating the required information budget constraint into the decision-making processes of statistical agencies. This means balancing the interests of data accuracy and privacy loss. A leading example of this process is the need for accurate redistricting data, to draw legislative districts and enforce the Voting Rights Act, and the protection of sensitive racial and ethnic information in the detailed data required for this activity. Wrestling with this tradeoff stares down the database reconstruction theorem, and uses the formal privacy results that it inspired to specify the technologies. Specifying the decision framework for selecting a point on that technology has proven much more challenging.

Director Abowd will be speaking in Ives 105.