Incorporating Mechanisms of Social Adoption in Design and Analysis of Stated-Choice Experiments

The use of stated-choice experiments in travel behavior research has increased dramatically over the past decade. Although considerable progress has been made, overprediction of market shares of new choice alternatives is often reported. This study is based on the contention that such overprediction is partly because experimental designs do not incorporate conditions that reflect how new alternatives are received in the marketplace: social adoption is not experimentally varied. The aim of this paper is to show how social adoption can be incorporated into the design and analysis of stated-choice experiments. The intention to buy an electric car is used for illustration. This paper discusses the design of the choice experiment and summarizes the main findings of the analyses. Results indicate that, although social influence plays a less significant role than attributes of electric cars in the buying process, different elements of social networks exert an influence on people's buying decisions. These effects vary between friends, relatives, colleagues, and the larger peer group. Moreover, the effects are nonlinear as the particular form of the part-worth utility function depends on the element of the social network. The latent decision to buy a car also depends on socio demographic variables. The results of this novel approach have implications for the design of stated-choice experiments.