“…Urban DID studies typically analyze the impact of a new housing investment or new infrastructure (e.g., a light rail line) using concentric rings to compare impacts within an inner ring with those in an outer ring. The radius of the ring varies widely, from as small as 500 feet for housing studies (e.g., Ellen et al, 2001), to the standard .25 mile radius for rail transit stations (e.g., Cao & Lou, 2018), to 500 to 1,000 meters for a wide variety of investments and interventions (Lee et al, 2020;Liang et al, 2020). In the Amazon HQ2 study, which is the study most similar to this one, the authors deployed circles of radii 1 mile from the Long Island City location and 5 miles from the Crystal City location, explaining that a more extensive radius was appropriate in the Virginia case because of commuters' reliance on cars.…”