Home Census Census data scrambling raises concerns in state

Census data scrambling raises concerns in state


A property northeast of the Springdale city limits has two ponds, two sheds and – according to the 2020 US Census – five residents.

This fictional occupation is not a mistake, said Jeff Hawkins, executive director of the Northwest Arkansas Regional Planning Commission. The Census Bureau deliberately added fake residents to some addresses and “subtracted” real residents from others in its publicly available data to protect household privacy.

“My favorite thing is that there are supposedly three people living on the grounds of the State Capitol in Little Rock,” Hawkins said of the jamming.

The bureau insists in public statements that, on average, the data is accurate. But this blurring of results is more likely to create problems the smaller a planner or researcher is or the more detail they are looking for, Hawkins said.

The situation is worse for researchers, said Mervin Jebaraj, director of the Center for Business and Economic Research at the University of Arkansas in Fayetteville. The problems will get worse, the two men said, especially as the Census Bureau plans to apply the same approach to the American Community Survey. The survey is an annual estimate that provides more detailed and up-to-date data between censuses. A complete census is carried out every 10 years.

“If you’re trying to divide a city into neighborhoods of equal population, that might not be a problem in Springdale with 22,000 people per neighborhood,” Hawkins said. “But if you do the same thing in Tontitown with 1,400 people per neighborhood, that causes problems. And some of the smaller towns can have 400 people per neighborhood.

“The smaller the area, the bigger the problem.”

Major cities will also face uncertainty, Hawkins said. For example, many federal grants are aimed at helping low- and middle-income neighborhoods, he said.

“I’ve seen these grants used for everything from fixing streets to buying a fire truck,” Hawkins said.

Census figures might incorrectly show a project would help low- and middle-income residents, but that might not be true, he said.

The scramble for privacy is already causing serious problems for economists, researchers and businesses, Jebaraj said. For example, detailed results showing where minorities live in fast-growing cities in northwest Arkansas cannot be trusted, he said.

By law, the Census Bureau must keep individual census responses confidential. The Internal Revenue Service, for example, cannot obtain a household’s census income data. But modern computerized numerical computation can sift through detailed census results and identify at least some households and their details within a census block, according to the office. If only a few residents report high or low household incomes, for example, analysis of the raw data collected can determine where they live.

A census block is the first and smallest unit in which household census responses are compiled. Most census blocks contain 250 residents or fewer, according to the bureau.

Any error in the data from the “disclosure avoidance system,” as the jamming is called, is negligible at the county level and above, the bureau’s analysis concluded, according to a Jan. 28 report.

Hawkins and Jebaraj did not dispute the county-level data average. Their contention is that county-level data is of little help to a school board trying to decide where to build an elementary school to serve a growing minority community or to a businessman deciding where to set up a store serving a specific group, such as newcomers to the region, they said.

“We rely heavily on data to make it all work,” Jebaraj said.

The Census Bureau used to exchange certain addresses between real people to ensure confidentiality. The system worked, Jebaraj said.

“Nobody ever violated it,” Jebaraj said of the privacy of US census data. “There is no case of that.”

Even if it were theoretically possible to identify individuals from census block data, he said, it would be much cheaper and faster to buy this information from private sources who collect it in the normal course of business, he said.

One of the worst effects of not having a clear picture below the county level is the inability to spot the start of a trend, Jebaraj said. For example, northwest Arkansas has recently seen South Asians come to the area, he said. A slight increase at the county level could be a very big increase for one of the smaller communities in that county, he said. Pinpointing such a trend in a way that is accurate and useful to researchers and planners would not be possible with the current quality of data, he said.

“We can go back,” Jebaraj said. The original unfiltered data on which all published data is based is still available to the office. The office, Congress or the courts could access it, he said.