Validation of a unidimensional and probabilistic measurement scale for proenvironmental behaviour by travellers

In the current debate, ecological themes have become a key element that can influence public policy, as recent events involving green activist groups have shown. Public policies targeted to education, along with focused advertising, can strongly influence people’s beliefs and their emotional reactions. Understanding individual behavioural responses is therefore of the utmost importance for policy makers wishing to encourage more sustainable mobility. They could be greatly assisted by an effective measure of ecological behaviour giving them a better understanding of the determinants of travel behaviour, enabling them to analyse the impact of adopted policies. Ideally, such a measure should be simple to use, and it should be usable across different cultural and geographical contexts so as to allow comparisons between different countries. This paper seeks to determine whether the General Ecological Behaviour (GEB) questionnaire – as a dichotomous multi-items Rasch scale for ecological behaviour measurement – is valid for use in a different cultural context. We refer to the relevant literature, and we describe our approach in detail so that it may easily be adopted by interested practitioners. The research was done in the metropolitan area of Torino (Italy), where a multimodal real-time smartphone application to assist travellers and encourage them towards more sustainable mobility was being developed and trialled. Within this framework, an investigation was done into the pro-environmental behaviour of the participants in the app trial. Our aim was to determine whether a general pro-environmental attitude can legitimately be assessed using Item Response Theory and, notably, the Rasch model. Results suggest that, using an Item Response Theory model, GEB is a questionnaire that is able to effectively measure pro-environmental behaviour by travellers. There are no discrepancies between pro-social behaviour (a trait that is known to correlate with environmentally friendly attitudes and that the GEB questionnaire seeks to measure) and actual environmentally friendly behaviour; one-dimensionality, item reliability, and the absence of simple differential item functioning are all good indicators of a model that functions well. GEB has shown its potential in providing an understanding of people’s attitudes towards environmental issues and of how this information might be used to better tailor public policies in a number of sectors, in particular transport.