When John Wilson became a King County, Wash., assessor two years ago, housing affordability was headed in a downward spiral, especially for the county’s low-income senior citizens, the disabled and disabled veterans.

To help older residents, the state provides a property tax exemption for homeowners over the age of 61 who are on fixed or low incomes. According to the 2017 American Community Survey (ACS) one-year Estimates, King County is home to 362,157 residents age 62 and over.

“We thought that King County’s enrollment level was low,” Wilson said, but he didn’t have the numbers to back up his hunch. “[So] we turned to the ACS to identify how many potential applicants were in King County and where they might be located.”

Wilson, along with King County demographer Chandler Felt and county epidemiologist Susan Kinne, used ACS Public Use Microdata Sample (PUMS) files to conduct a customized inquiry that met the program’s eligibility criteria.