In a choice experiment setup considering a non-market good, this paper adds to the literature on survey mode effects by providing evidence that internet surveys can be a viable alternative to traditional mail surveys when gathering feedback from a sample of respondents. The case study concerns preferences for protecting different types of landscape from road encroachment when building new motorways in Denmark. Two samples of respondents are surveyed-one by internet and one by mail. The performances of the two samples are compared over six different criteria; response rates, protest responses, demographics, preferences and WTP, estimation precision, and, finally, certainty in choice. Differences are observed for some of these criteria, implying that analysts should be aware that choosing internet over mail could be accompanied by a survey mode effect. However, the observed differences do not translate into significant differences in the unconditional WTP estimates. In most applied economic valuation studies of non-market goods, the main objective is in fact estimation of WTP. Hence, in the present case, the identified survey mode effects do not severely invalidate the applicability and continued use of the internet as a suitable means of collecting data for choice experiment economic valuation of non-market goods.
