There are two basic ways of modeling such aggregate (or group) behavior. One approach
directly models the aggregate share of all or a segment of decision makers choosing each
alternative as a function of the characteristics of the alternatives and socio-demographic
attributes of the group. This approach is commonly referred to as the aggregate approach. The
second approach is to recognize that aggregate behavior is the result of numerous individual
decisions and to model individual choice responses as a function of the characteristics of the Self Instructing Course in Mode Choice Modeling: Multinomial and Nested Logit Models 2
Koppelman and Bhat January 31, 2006 alternatives available to and socio-demographic attributes of each individual. This second approach is referred to as the disaggregate approach.