A new interpretation of the “normalizing” or “balancing” factors of gravity-type spatial models

As the title implies, this paper provides a new way of viewing the so-called “normalizing” or “balancing” factors of generalized gravity-type spatial models. This new interpretation—a more precise version of an earlier interpretation offered by Wilson—is made in terms of the notions of origin and destination accessibilities which are shown to implicitly underly the model.The first part of the paper discusses several previous interpretations of balancing factors. The notions of origin and destination accessibilities are presented in the second section. The third section provides new interpretations of balancing factors in terms of these accessibility notions. The fourth section presents some new modeling results which are made possible by this new interpretation of balancing factors. The fifth and final section of the paper discusses a potentially fruitful direction for further research.