The effects of presentation formats in choice experiments

Although stated-preference surveys take various forms, the use of either text or visuals to represent attributes is uncontroversial and remain commonly used. While prior research has investigated the impact of these formats in other disciplines, little is known about their effects in terms of relative importance in environmental economics. We conduct surveys on households’ preferences for water efficient technologies in South Africa, where we compare three presentation formats, namely text, visuals, and both text and visuals. Survey data collected from 894 households in the Gauteng Province are analysed using the mixed-logit model to test whether these three formats generate differences in estimated utilities and marginal willingness-to-pay (MWTP). This research sheds light on how to develop a valid presentation method for attribute levels in choice experiments, which is critical considering most environmental economics goods and services are not traded in the market. Our results obtained from the various presentation methods differ. There were also differences in MWTP estimates between the three groups. This suggests that the presentation format has significant impacts on choice. Thus, more research on presentation formats in environmental economics is warranted.