When Privacy Protection Goes Wrong: How and Why the 2020 Census Confidentiality Program Failed

The US Census Bureau implemented a new disclosure control strategy for the 2020 Census that adds deliberate error to every population statistic for every geographic unit smaller than a state, including metropolitan areas, cities, and counties. This article traces the evolving rationale for the new procedures and assesses the impact of the 2020 disclosure control on data quality. The Census Bureau argues that the traditional disclosure controls used for the 2010 and earlier censuses revealed the confidential responses of millions of Americans. I argue that this claim is unsupported, and that there is no evidence that anyone's responses were compromised. The new disclosure control strategies introduce unnecessary error with no clear benefit; in fact, the new procedures may actually be less effective for protecting confidentiality than the procedures they replaced. I conclude with recommendations for minimizing disclosure risk while maximizing data utility in future censuses.