Protest Responses in Contingent Valuation

A significant number of respondents to contingent valuation surveys tend to either state a zero bid, or refuse to state a bid at all, for reasons associated with the process of valuation. These protest responses are routinely removed from contingent valuation samples because it is assumed that they are not indicative of respondents’ ‘true’ values. The censoring of protest responses has led to the emergence of a definitional controversy. One view is that the definition of protest responses and the rules for censoring them are dependent on whether the practitioner conceives of the contingent valuation survey as a market or as a referendum. However, what is not acknowledged is the possibility that protest responses and their meaning may vary according to the type of good being valued, the elicitation format, and the interaction between these elements and external factors. This potential renders the development of unambiguous rules for censoring protest responses difficult. Moreover, when willingness to pay is viewed as a behavioural intention, it becomes important to determine what the responses actually mean. This approach does not assume an interpretative position a priori against which the responses should be judged, but seeks to inform an existing understanding which is inadequate.