Myths, (Mis)Perceptions and Reality in Measuring Voluntary Behavioural Changes

Abstract

Increasing interest in ‘soft’ policy approaches to travel demand management, poses the question of how to measure the effectiveness of interventions. Much of the focus has been on statistical reliability of measured change where sample surveys are the primary means of estimating change. Sample surveys also pose issues of non-sampling errors, especially when the ‘measure’ is the difference between ‘before’ and ‘after’. This paper outlines the principles and pitfalls in measuring behaviour change. It draws on voluntary travel behaviour change (VTBC), using a number of approaches, including but not limited to Individualised Marketing (a method developed by the authors). A key issue in VTBC is the extent to which repeated experience can validate the effectiveness of voluntary behaviour change interventions in general, despite statistical errors of individual measurements. Measurement is fundamental to evaluation of outcomes. It can also aid the selection of locations with high potential to achieve change through identification of key success factors. In the specific case of travel behaviour change, there is now a substantial body of research that potentially allows outcomes to be related to other factors. To date, no strong relationships have been identified, but this would be a useful area for further research. Experience does demonstrate, however, that the scale of the intervention is important. Interventions with more than 5000 households are consistently more successful than small ones, even allowing for the greater statistical variability of measurement for smaller projects. Large scale also offers opportunities for intervention design to benefit from the potential for diffusion beyond those directly involved in the project.

Citation

Brög, W. and Ker, I. (2009), "Myths, (Mis)Perceptions and Reality in Measuring Voluntary Behavioural Changes", Bonnel, P., Lee-Gosselin, M., Zmud, J. and Madre, J.-L. (Ed.) Transport Survey Methods, Emerald Group Publishing Limited, Leeds, pp. 81-111. https://doi.org/10.1108/9781848558458-005