Blog by David Friedman: “This is a story about data manipulation. But it begins in a small Nebraska town called Monowi that has only one resident, 90 year old Elsie Eiler.
The sign says “Monowi 1,” from Google Street View.
There used to be more people in Monowi. But little by little, the other residents of Monowi left or died. That’s what happened to Elsie’s own family — her children grew up and moved out and her husband passed away in 2004, leaving her as the sole resident. Now she votes for herself for Mayor, and pays herself taxes. Her husband Rudy’s old book collection became the town library, with Elsie as librarian.
But despite what you might imagine, Elsie is far from lonely. She runs a tavern that’s been in her family for 50 years, and has plenty of regulars from the town next door who come by every day to dine and chat.
I first read about Elsie more than 10 years ago. At the time, it wasn’t as well known a story but Elsie has since gotten a lot of coverage and become a bit of a minor celebrity. Now and then I still come across a new article, including a lovely photo essay in the New York Times and a short video on the BBC Travel site.
A Google search reveals many, many similar articles that all tell more or less the same story.
But then suddenly in 2021, there was a new wrinkle: According to the just-published 2020 U.S. Census data, Monowi now had 2 residents, doubling its population.
This came as a surprise to Elsie, who told a local newspaper, “Then someone’s been hiding from me, and there’s nowhere to live but my house.”
It turns out that nobody new had actually moved to Monowi without Elsie realizing. And the census bureau didn’t make a mistake. They intentionally changed the census data, adding one resident.
Why would they do that? Well, it turns out the census bureau sometimes moves residents around on paper in order to protect people’s privacy.
Full census data is only made available 72 years after the census takes place, in accordance with the creatively-named “72 year rule.” Until then, it is only available as aggregated data with individual identifiers removed. Still, if the population of a town is small enough, and census data for that town indicates, for example, that there is just one 90 year old woman and she lives alone, someone could conceivably figure out who that individual is.
So the census bureau sometimes moves people around to create noise in the data that makes that sort of identification a little bit harder…(More)”.