Burchfield, et al., “Causes of Sprawl: A Portrait from Space,” Quarterly Journal of Economics, CXXI (2006), 587–633, show that variables chosen from the monocentric model and its generalizations as well as those capturing geographical and political characteristics of urban areas are important in explaining urban sprawl, as measured by an index of the amount of undeveloped land around an average dwelling. Although Burchfield, et al., draw on the urban monocentric model and its extensions, they do not, with one exception, employ the exogenous variables of that model. On the other hand, with one recent exception, urban economists do not use geographical and political characteristics to explain sprawl, defined as the spatial size of the urban area. We were interested, therefore, in seeing if combining these two sets of variables better explains these two measures of sprawl. The main findings of this paper are (1) the standard monocentric model variables fail to contribute to an explanation of the sprawl index, (2) these variables are, however, very important in explaining the spatial size of urban areas, and (3) the Burchfield, et al., variables contribute to an explanation of the spatial size of urban areas. We conclude with a summary and some comments on the role of theory in providing empirically testable hypotheses. We call for efforts to develop a theory comparable to the monocentric model to explain the Burchfield, et al. (2006), measure of sprawl.
