411 – Protecting Privacy While Maximizing the Utility of Government Data: Evaluating Current Approaches and Exploring New Alternatives
Developing and Testing the Microdata Analysis System
Michael Freiman
U.S. Census Bureau
Amy Lauger
U.S. Census Bureau
Marlow Lemons
U.S. Census Bureau
Bryan Schar
U.S. Census Bureau
Kyle Hasenstab
The Census Bureau is developing a Microdata Analysis System (MAS) that will provide custom tables and other analyses based on user specifications. The underlying microdata will be fully protected because calculations for the MAS will take place behind two firewalls and only the final output will be provided to the user. Results will be given only if the output passes a set of disclosure rules. We describe the planned capabilities of the MAS, as well as the testing and evaluation of the disclosure protection measures and some attacks that are being evaluated to ensure that the system only gives data that are safe to release. We focus on assessing and preventing one type of attack: a differencing attack in which the user produces the same table for two very similar universes and subtracts the numbers in the two tables to reveal information about an individual respondent. We consider the prevalence and risks of such an attack in the absence of protections and how the disclosure measures in place protect against an attack.