Yes. Radon levels vary substantially between adjacent homes because foundation type, slab condition, sealing quality, and HVAC dynamics all differ even on the same lot or block. Cincinnati neighborhood-level averages do not predict individual-home readings.
More detail
Cincinnati radon data shows clearly that adjacent homes can differ by an order of magnitude on radon readings. The 1925 Tudor with a stone basement and original mortar joints might read 14 pCi/L while the 1955 ranch next door reads 1.2 pCi/L. The geology under the lot is similar; what differs is the building envelope. Five specific factors that drive same-block variation in Cincinnati: (1) foundation type (stone basement vs slab vs crawl space vs walkout), (2) age and condition of slab penetrations (sump pits, plumbing rough-ins, expansion joints), (3) presence of a passive RRNC stack from post-2010 construction, (4) HVAC equipment location and basement air-pressure dynamics, and (5) presence of any active waterproofing or sealing work done over the years. Even on the same lot, a finished-basement reading often differs from an unfinished-basement reading because the air-pressure profile differs. The cost of testing is so low ($15 to $30 for a hardware-store kit, $150 to $300 for a professional continuous radon monitor) relative to the cost of unnecessary mitigation that the universal recommendation is test-every-home, regardless of what neighbors are reading. Cincinnati realtor practice tracks this: real-estate radon contingencies attach to individual homes, not neighborhoods, because lender experience confirms the same-block variation.