ABSTRACT
Ewing originally estimated a single county sprawl index for each of 448 metropolitan counties or statistically equivalent entities. A census block is defined as a statistical area bounded on all sides by streets, roads, streams, railroad tracks, or geopolitical boundary lines, in most cases. A traditional urban neighborhood is composed of intersecting bounding streets that form a grid, with houses built on the four sides of the block, facing these streets. In updating the original county sprawl index to 2010, five of the six variables were derived in the exact same way as for 1990 and 2000. The NIH website also contains estimates of county sprawl in 2000, derived by applying the 2010 component score coefficient values to data for counties in 2000. It also presents changes in country sprawl, measured equivalently, between the two census years.
