An exploratory analysis of the effect of numbers of choice sets in designed choice experiments: an airline choice application

Stated choice (SC) experiments are increasingly adopted as the empirical so urce of information on how individuals respond to current and potential tra vel contexts. The accumulated experience with SC data has been heavily cond itioned on analyst prejudices about the acceptable complexity of the data c ollection instrument, especially the number of profiles (or treatments) giv en to each sampled individual (and the number of attributes and alternative s to be processed). It is not uncommon for analysts to impose very stringen t limitations on the complexity of an SC experiment. A review of the litera ture suggests that very little is known about the basis for rejecting compl ex designs or accepting simple designs. In this paper, we develop a complex design as the basis for an SC study, producing a fractional factorial of 3 2 rows. However, we then truncate the fraction by administering 4, 8, 16, 2 4 and 32 profiles to a sample of individuals in Australia and New Zealand f aced with the decision to fly (or not to fly) between Australia and New Zea land by alternative airlines and fare regimes. Statistical comparisons of e lasticities (an appropriate behavioural basis for comparisons) suggest that the empirical gains within the context of a linear specification of the ut ility expression associated with each alternative in a discrete choice mode l may be quite marginal. (C) 2001 Elsevier Science Ltd. All rights reserved .