Modelling social norms: Case study of students' car purchase intentions

In this paper we aim to quantify the influence of social norms on car ownership intention by estimating ordered hybrid choice models (OHCM) with car purchase intention as dependent variable. Our sample consists of 1229 university students from three developed and four developing countries. We construct subjective social norms (SSN) by interacting the perceived expectation to buy a car with motivation to comply with the expectation. Four approaches to incorporate social norms into OHCM are presented while controlling for other explanatory variables such as attitudes and socio-demographics. From the four estimated models we find that social norms significantly correlate with car purchase intention. Though differently defined in the four models, we find similar parameter estimates in all models, which leads us to conclude that the effect is fairly robust even with simplified definitions. From a model with person-group specific observed SSN, we further find though that group specific influences can differ significantly and that parents and university peers significantly influence car purchase intention. (C) 2016 Hong Kong Society for Transportation Studies. Published by Elsevier Ltd. All rights reserved.