Temporal stability of individual preferences for river restoration in Austria using a choice experiment.

Temporal stability of values (environmental preferences) is usually considered to be an indicator of the reliability of a valuation instrument because the values can be "reproduced" by follow-up experiments. The objective of this paper is to test temporal stability of individual preferences for river restoration by employing two identical choice experiments with a time difference of one year. We compared the results of two surveys carried out on the stretch of the Danube River between the Austrian capital of Vienna and the border to the Slovak Republic in 2007 and 2008. The choice experiment method considered economic costs and benefits of ecological improvements along the river, in order to value environmental resources. Using a multinomial logit and a mixed logit model for the two samples and a pooled sample, we found that preferences and willingness-to-pay estimates for program attributes are not sensitive to time. The results suggest that, in the absence of an extreme event, individual preferences are robust over a short time period.