Browsing through the plethora of 2020 census figures could break a person.
When the data was released last month, one of the numbers for Prince William County and its cities last month didn’t appear to match the others.
The population of Northern Virginia increased by 14.3% and the combination of Prince William, Manassas and Manassas Park increased by 19.3%. Dumfries jumped 14.5%, Occoquan was up 10.8% and even tiny Quantico was up 20.4%.
But amid all the increases, Haymarket posted a relatively drastic 13.3% drop, or 237 residents, from 1,782 in 2010 to 1,545 in 2020.
Haymarket was one of only three incorporated towns in Northern Virginia to lose residents, joining Clifton and Middleburg.
So are Haymarket’s numbers correct? At least one demographer says mostly, but it’s complicated.
Census data is divided into several different categories in various geographic areas, including state, locality, congressional districts, and master districts.
The numbers are also broken down into what are called blocks, groups of blocks and leaflets. Blocks are the smallest set of data and can, as the name suggests, only cover one block. A connected set of these are combined into groups of blocks, which are then grouped into leaflets.
Researchers have sounded the alarm bells about new methods used in the 2020 census that have muddied the numbers as data is examined in smaller geographic areas.
The problem with the 2020 data is that a computer algorithm puts people where they don’t actually live and scrambles demographics about age and race to protect privacy. The researchers say the method does not affect numbers in the larger geographic area, but can cause problems as the dataset gets smaller and smaller.
Hamilton Lombard, a demographer at the Weldon Cooper Center at the University of Virginia, extracted the sectors and census blocks for Haymarket, Clifton, and Middleburg and compared the numbers to 2010.
Clifton lost 39 residents and Middleburg lost four, which Lombard says appears to be symbolic of numbers issues in small areas.
In Haymarket, however, one particular area stood out, so Lombard used the county’s real estate records and satellite imagery to examine the area. Based on this look, it appears that while Haymarket may have been somewhat affected by the algorithm, it was overcharged in 2010 by showing almost 200 people living on vacant land.
Lombard said it appeared the 2020 census had corrected the 2010 error, helping to reduce the population.
The city limits of Haymarket are shaped like a rectangle centered around Va. 55. A small portion of the city is on the north side of Interstate 66 and includes half of the Haymarket Park & Ride and the I-66 interchange with US 15.
The area in question is at the interchange. County real estate records show an approved subdivision of approximately 27 parcels off Old Carolina Road. Five houses were built on six plots and, according to county records, were built long before the 2010 census.
Lombard said the 2010 census showed nearly 200 people living in the undeveloped area, and it is extremely unlikely that any housing estate that existed in 2010 was bulldozed.
The only visible changes in the area between the satellite images of January 2012 and June 2021 are a larger interchange and the park-and-ride lot.
Lombard said the situation in Haymarket, unfortunately, is more the exception than the rule with population counts in small towns.
“It’s kind of a pleasant surprise,” he said.