Census

Challenge

The U.S. Census, which counts every resident in the United States every 10 years, is vital for determining the number of seats each state holds in Congress, measuring economic performance, and helping the government decide where and how to distribute federal funding. Public Census data also serves as a critical resource for state and local governments, researchers, journalists, and businesses, helping them analyze trends in demographics, economics, and public policy.

However, ensuring both accuracy and privacy presents a fundamental challenge. Census data must be precise enough to be useful while also protecting respondents’ personal information.

The question becomes: How can sensitive Census data be safeguarded while still enabling  accurate statistical analysis? 

Solution

To address this challenge, the Census Bureau adopted Differential Privacy, a state-of-the-art approach that introduces statistical noise to data query responses, ensuring that aggregate statistical results remain significant and useful while preventing the identification of specific individuals. This obfuscation technique offers strong mathematical guarantees of privacy, making it possible to share useful data while maintaining individual privacy.

Galois worked with the Census Bureau from 2019–2025 to conduct independent audits of its Differential Privacy framework. By rigorously evaluating the implementation of privacy-preserving algorithms, Galois helped ensure that the Census Bureau’s methods are both technically sound and aligned with their privacy objectives. We also developed tools to analyze and quantify the threat of potential privacy attacks on individuals.

Value Add

• Expert Validation: Galois provided independent, expert assessment of the Census Bureau’s privacy safeguards.
• Balancing Utility and Privacy: We verified that Differential Privacy implementations functioned correctly and effectively balanced data utility with individual privacy.
• Risk Mitigation: Our work helped the Census Bureau proactively identify and address potential vulnerabilities before they impacted data integrity or confidentiality.
• Bolstering Public Trust: Our efforts helped both the U.S. government and the American people by ensuring that Census data remains both private and useful, reinforcing trust in public data systems.
• ‍Innovation Leadership: By applying cutting-edge research in privacy-preserving computation, Galois contributes to the advancement of secure data-sharing methodologies.