Does “No” mean “No”? A protest methodology

In this paper, we propose a method of identifying and truncating protesters in Contingent Valuation surveys. We propose using a system of Willingness to Pay (WTP) questions that value multiple goods and that use both discrete choice and open-ended questions coupled with multiple questions about protest beliefs administered to the entire sample. Protesters can then be identified because they reject all bids, declare zero on all open-ended questions, and hold protest beliefs. The proposed procedure has been empirically tested on an air pollution data set from Poland, where 27 of the sample was identified as protesters. The adjustment for protesters increased the estimated WTP values by a factor of more than 3. Copyright Springer Science+Business Media, Inc. 2007