Ambivalent statements in contingent valuation studies: inclusive response formats and giving respondents time to think

A recent concern in the valuation literature is the uncertainty respondents feel when posed with willingness-to-pay questions for environmental amenities in hypothetical market scenarios. Using a multiple-bounded discrete-choice format, the results indicate that respondents become less ambivalent when allowed considerable time to think about the valuation task before a response is elicited. In particular they tend to reduce the reported willingness to pay associated with low certainty of paying, hence resulting in more conservative welfare estimates. Implications for the application of environmental valuation techniques are discussed. Copyright 2007 The Author 2007 Australian Agricultural and Resource Economics Society Inc. and Blackwell Publishing Ltd .

Contemporary Guidance for Stated Preference Studies

This article proposes contemporary best-practice recommendations for stated preference (SP) studies used to inform decision making, grounded in the accumulated body of peer-reviewed literature. These recommendations consider the use of SP methods to estimate both use and non-use (passive-use) values, and cover the broad SP domain, including contingent valuation and discrete choice experiments. We focus on applications to public goods in the context of the environment and human health but also consider ways in which the proposed recommendations might apply to other common areas of application. The recommendations recognize that SP results may be used and reused (benefit transfers) by governmental agencies and nongovernmental organizations, and that all such applications must be considered. The intended result is a set of guidelines for SP studies that is more comprehensive than that of the original National Oceanic and Atmospheric Administration (NOAA) Blue Ribbon Panel on contingent valuation, is more germane to contemporary applications, and reflects the two decades of research since that time. We also distinguish between practices for which accumulated research is sufficient to support recommendations and those for which greater uncertainty remains. The goal of this article is to raise the quality of SP studies used to support decision making and promote research that will further enhance the practice of these studies worldwide