Utility Variability within Aggregate Spatial Units and its Relevance to Discrete Models of Destination Choice

Abstract

In this chapter, we examine a logit model designed specifically for spatial choice among aggregate destinations. Typically, the logit and gravity models are applied to problems of spatial interaction without due consideration for the aggregation scale of the data. There is of course a general awareness that models estimated at different levels of aggregation will yield different parameter estimates but most researchers proceed directly with their analysis at the aggregate level and make no adjustments. Research on aggregation issues has been intertwined with work on the ‘modifiable areal unit problem’. This research examines how spatial Statistical models and diagnostics are affected by the aggregation scale and spatial configuration of spatial units. Choice processes per se, as are present in all problems of spatial interaction, are not specifically addressed in this body of research. Rather the focus is on the univariate or bivariate spatial processes associated with one or two spatially-referenced attributes [Openshaw (1984) and Arbia (1989)]. Aggregation issues are relevant in both scenarios but as will be illustrated in this chapter, the theoretical framework to accommodate aggregation in a choice context is quite different from that considered in analysis of the modifiable areal unit problem.