Individual preferences for food items within couples: Validating choice experiments predictions with real purchases data

Despite the popularity of choice experiments (CEs) for the valuation of environmental goods and services, some of its shortcomings have been only partially addressed by the literature. Among these, of particular saliency are the hypothetical nature of CEs and the lack of information on joint choices (e.g. choices made by couples) in traditional CEs. In this study, we contribute to filling these gaps by investigating joint choices concerning cheeses produced via different processes, involving environmental and social sustainability features. We use a two-stage preference elicitation approach, using first stated and then real consumption choices collected from a sample of 90 couples. In the first stage, each member of the couples separately took part in a web survey with a hypothetical CE. In the second, these couples jointly engaged in a field experiment with monetary incentives in which they jointly chose the cheeses to purchase. This approach allows us to evaluate the role of individual preferences in shaping joint choices and to investigate whether predictions from stated-choice data are congruent with, and validated by, real purchase data. We use CE data to estimate individual preferences with discrete choice models and use joint purchase data via the Multiple Discrete-Continuous Nested Extreme Value model. Results suggest that joint real choices follow a substantively different decision process from that of individual stated choices.