The Census: Protecting Privacy versus Creating Useless Data

“Differential Privacy:” A statistical adjustment system that may render 2020 census population data unusable.

“Differential Privacy:” A statistical adjustment system that may render 2020 census population data unusable.

Every ten years the U.S. conducts a census in an attempt to count every person once, only once, and in the right place. The U.S. Census Bureau does not release or provide information about individual people or households. Instead, it releases tables and counts of population data

Historically, the Census Bureau has been able to protect information about individuals through a “disclosure avoidance system." However, with the advent of sophisticated data mining techniques, the Bureau is concerned that its existing system will not prevent information on individuals from being ferreted out of tables when it releases results from the 2020 census. 

Because of this concern, the Bureau has been working for several years on a new, elaborate disclosure avoidance system known as “Differential Privacy,” (DP) which statistically adjusts data. Differential Privacy is the Bureau’s attempt to strike a balance between providing the highest level of data accuracy in the tables it releases, which would provide minimal privacy protection, vs. virtually 100 percent privacy, which would result in data so erroneous that they are not usable. 

As the Bureau grapples with the privacy vs. accuracy issue, it has been releasing a series of “demonstration products” using data from the 2010 census so census stakeholders can see the kinds of changes DP will make and determine the impact it would have on their work. 

I looked at Washington state’s census block population data, and the four-county area of Island, San Juan, Skagit, and Whatcom counties (to evaluate small-area-population-data). I have tested the impacts of DP and assessed that the errors it introduces are substantial. I believe similar errors will be found in other states as well. Further, I believe that if they are applied nationwide, they will render the country’s block level data essentially unusable.

You can read my full paper on the four-county area here.  

And here are links to a paper on the effect of Differential Privacy on the state as a whole, and one that looks at Alaska, respectively

Attached Files

About David A. Swanson

Posting Citizen Journalist • Member since Mar 31, 2020

David A. Swanson is Edward A. Dickson Emeritus Professor of Sociology, University of California Riverside. He served as a member of the U. S. Census Bureau’s Scientific Advisory Committee [...]

Comments by Readers

John Servais

May 27, 2021

The Washington Post has this morning posted an article on the Census Bureau attempt to water down and perhaps make useless the 2020 census data.  Their article quotes several times from David Swanson’s full technical article which is linked from the summary article above.

You can read the WAPost article here - or at the Associated Press website here.  

David is a regular writer and citizen journalist with NW Citizen.  NWCitizen readers had this information a week ago.  While we focus on local issues, all our writers are local residents and will post articles with new information of state and national interest.  Others who frequently do are Dick Conoboy and Michael Riorden.  Congrats David for your writing being quoted by the Washington Post.

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