Spatial distribution of retail sales

We examine the distribution of sales for a retail chain in the Houston market using a spatial gravity model. Unlike previous empirical studies, our approach models spatial dependencies among both consumers and retailers. The results show that both forms of spatial dependence exert statistically and economically significant impacts on the estimates of parameters in retail gravity models. Contrary to the suggestions of (Gautschi, D. A. (1981). "Specification of Patronage Models for Retail Center Choice," Journal of Marketing Research 18, 162-174.) as well as (Eppli, M. J., and J. D. Shilling. (1996). "How Critical Is a Good Location to a Regional Shopping Center?" Journal of Real Estate Research 12, 459-468.), our results show the importance of the distance parameter in retail gravity models may be greatly understated. Thus, ignoring spatial dependence may lead to overestimation of the deterministic extent of trade areas, and underestimate the importance of good locations.