Choice behavior can be viewed as probabilistic. As a result, it is unlikely that any given alternative will be selected exclusively unless no other alternatives exist. This proposition can be expressed symbolically as follows:

where Pij is the probability that an individual i will select alternative j given the utility of j relative to the sum of the utilities of all other choices of which there are n considered by individual i. A more detailed explanation of Dr. Huff's work and the enhanced capabilities of the model can be found in the October–December 2003 ArcUser magazine ("Parameter Estimation in the Huff Model" [PDF-1.4 MB]).

See also "Dr. David L. Huff Joins Esri as Technical Advisor."