Measures of Urban Patterns in Large Urban Areas in the U.S., 1950-2010

Patterns of housing unit distributions in 59 large urban areas in the United States from 1950 to 2010 were evaluated using 4 measures: density, the index of dissimilarity for variation in density, the centralization ratio, and Moran’s I for clustering. The mean values for the first 3 measures consistently declined over the period, but wide variation was observed among the urban areas with both large increases as well as large decreases. The measures were correlated with one another as expected. Simple multivariate analysis showed centralization and clustering to be strongly related to variation with weak or no direct relationship with density. Larger urban areas exhibited greater complexity, tending to have higher values for all 4 measures. Average values varied by region, with areas in the Northeast generally having the highest values while those in the South were consistently lowest. However, a significant shift occurred with urban areas in the West changing from having below-average densities in 1950 to the highest densities in 2010. Cluster analysis was used to develop a typology of urban areas in 2010, classifying them into 6 groups