DHS maps out data sharing with Census Bureau

The Trump administration's plan to include a citizenship question in the 2020 census questionnaire sent to every U.S. household was thwarted by a June 2019 Supreme Court ruling issued just days before a printing deadline.

Just two weeks later, President Donald Trump issued an executive order to allow the Commerce Department on behalf of the Census Bureau to obtain federal agency data on immigration to generate data on the size of the immigrant population, including details on documentation and legal status from the 2020 census responses.

On Dec. 27, the Department of Homeland Security publicly released a privacy impact assessment that offered the first look at the details of the immigration data that Customs and Border Protection, Immigration and Customs Enforcement and U.S. Citizenship and Immigration Services plans to share with the Census Bureau.

This is apparently the first time DHS has been asked to share personally identifiable information on immigrants and visitors in its systems with the Census Bureau, although USCIS does share anonymized data on lawful permanent residents and naturalized citizens with Census in an agreement dating back to 2007.

Data on travel, immigration and enforcement will be used as new input into census records on individual people, along with administrative data from other agencies. According to the privacy assessment, DHS data will assist in helping to identify residents that don't have a Social Security number or a tax identification number with IRS. That will likely reduce the number of U.S. residents that can't be matched with a Census individual identifier called a protected identification key (PIK).

Additionally, citizenship and immigration data will be used in the creation of a statistical model designed to measure the "citizenship probability" of each individual with a PIK in Census systems. That metric, in turn, will inform the development of statistics on the citizen voting age population.

Data held by various DHS components, the privacy assessment states, is decentralized due to complex, overlapping records in different systems. The document acknowledges the risk that Census could use the DHS data to assign incorrect immigration status, but it states that the data generated by the census using 2020 responses will be aggregated to give a picture of citizenship at the level of a "census block" and won't reveal information on any individuals.

Another risk is the ability of the Census Bureau to process the DHS data, which comes from individual systems and has its own tags and identifiers. "Linking records between datasets is not likely to be 100% accurate," the document states.

According to the text of the executive order, the combined Census and DHS data won't be used in immigration enforcement, and federal law spelled out in Title 13 of the U.S. Code prohibits Census from releasing personally identifiable information to law enforcement.

The executive order signed by Trump states that "information subject to confidentiality protections under Title 13 may not, and shall not, be used to bring immigration enforcement actions against particular individuals. Under my Administration, the data confidentiality protections in Title 13 shall be fully respected."

When the order was first released in July, privacy advocates cautioned about the potential for abuse. In a July 23 letter to the House Committee on Oversight and Reform, Marc Rotenberg, president of the Electronic Privacy Information Center, noted that the order has the intentions of generating data on non-citizens in the U.S. and identifying non-citizens.

"While the first goal contemplates the creation of statistical records that could be useful for public policy determinations, the latter implicates fundamental due process rights and will impact both citizens and non-citizens," Rotenberg said.