Abstract: |
Spatial choices entailing many alternatives (e.g., residence, trip
destination) are typically represented by compensatory models based on utility
maximization with exogenous choice set generation, which might lead to
incorrect choice sets and hence to biased demand elasticity estimates.
Semi-compensatory models show promise in increasing the accuracy of choice set
specification by integrating choice set formation within discrete choice
models. These models represent a two-stage process consisting of an
elimination-based choice set formation upon satisfying criteria thresholds
followed by utility-based choice. However, they are subject to simplifying
assumptions that impede their application in urban planning. This paper
proposes a novel semi-compensatory model that alleviates the simplifying
assumptions concerning (i) the number of alternatives, (ii) the representation
of choice set formation, and (iii) the error structure. The proposed
semi-compensatory model represents a sequence of choice set formation based on
the conjunctive heuristic with correlated thresholds, and utility-based choice
accommodating alternatively nested substitution patterns across the
alternatives and random taste variation across the population. The proposed
model is applied to off-campus rental apartment choice of students. The
population sample for model estimation consists of 1,893 residential choices
from 631 students, who participated in a stated-preference web-based survey of
rental apartment choice. The survey comprised a two-stage choice experiment
supplemented by a questionnaire, which elicited socio-economic
characteristics, attitudes and preferences. During the experiment, respondents
searched an apartment dataset by a list of thresholds for pre-defined criteria
and then ranked their three most preferred apartments from the resulting
choice set. The survey website seamlessly recorded the chosen apartments and
their respective thresholds. Results show (i) the estimated model for a
realistic universal realm of 200 alternatives, (ii) the representation of
correlated threshold as a function of individual characteristics, and (iii)
the feasibility and importance of introducing a flexible error structure into
semi-compensatory models. |