Should differential privacy be used in the U.S. census?


Answer: I disagree with the US Census Bureau in its use of differential privacy for reasons as follow. The main purpose of the US Census is enumeration – to correctly count the population such that resource distribution can be performed smoothly and properly in the future. The use of differential privacy essentially undermines this goal. Although populations at the state level would remain true to the raw data, those at the town level could be subject to much higher variances. For example, the New York Times article “Changes to the Census Could Make Small Towns Disappear” exemplifies how differential privacy could compromise the enumerative purpose of the US Census. Native American towns that are much less populated than the urban districts could see their population numbers being halved by the DP algorithm. In addition, these incorrect numbers for Native Americans mean more than a mere calculation mistake – it could bring real-world consequences like reduced fundings or inadequate political representation. Yet, isn’t the US Census counting the population such that everyone can receive federal resources and form political constituency equally and equitably? Therefore, the use of differential privacy essentially negates the Census’s purpose.

Besides the more material concern illustrated above, I argue that the use of differential privacy could also lead to a much more social and cultural issue – representation. The New York Times article has revealed that our society has adopted algorithms that always attend to the majority at the expense of the minority, and such logic behind the algorithmic design would push the representation issue into a vicious cycle. Native American people, whose land was brutally taken away and colonized, have been historically rendered as a minority group in the society. All talks on land reparations aside, the US Census Bureau has designed and passed after checks an algorithm that diminishes their very existence on the spreadsheet. What does this imply about the logic behind the implementation of differential privacy? If the Census Bureau is fully aware that most of the Native American towns are rather sparsely populated, and the algorithm to preserve differential privacy would lead to high variances for estimation of small populations, what does the implementation of this algorithm imply? That this group of people are fine with not being represented in the final headcount, even if they have spent time and money in the process? This show of negligence again invalidates the use of differential privacy in the US Census.