A Meta-study Investigating the Sources of Protest Behaviour in Stated Preference Surveys

It is a well-known empirical finding that some percentage of respondents participating in Stated Preference surveys will not give responses that reflect their true preferences. One reason is protest behaviour. If the distribution of protest responses is not independent of respondent or survey characteristics, then simply expelling protesters from surveys can lead to sample selection bias. Furthermore, WTP estimates will not be comparable across surveys. This paper seeks to explore potential causes of protest behaviour through a meta-study based on full datasets from 38 different surveys. The objective of the study is to examine the effect of respondent specific variables as well as survey specific variables on protest behaviour. Our results suggest that some of the differences in WTP typically observed between different demographic groups, different elicitation formats and different question formats might actually be attributed to inherent differences in the propensity to protest. Our results indicate that the propensity for respondents to exhibit protest behaviour when asked a stated preference type valuation question depends on a number of specific factors, respondent specific as well as survey specific—knowledge which could be used in order to reduce protest behaviour.     

Protesting and Justifying: A Latent Class Model for Contingent Valuation with Attitudinal Data

This article develops a latent class model for estimating willingness-to-pay (WTP) for public goods using simultaneously contingent valuation (CV) and attitudinal data to identify individuals with similar characteristics, such as WTP and protest attitudes. We find evidence that the answer to the CV question influences the responses to the attitudinal questions. In our case, this influence reflects rational behavior (budget constraint issues) and justification biases related to protest reasons, such as lack of trust in institutions or fairness issues with respect to the distribution of the burden of preservation. The results from our empirical application confirm the importance of accounting for those biases.     

Modeling self-censoring of polluter pays protest votes in stated preference research to support resource damage estimations in environmental liability

The identification and treatment of protest response in stated preference (SP) research such as contingent valuation is an underdeveloped area. Protest related to the polluter pays principle (PPP) is expected to pose an important hurdle to the application of SP research in environmental liability claims, for instance under the European Environmental Liability Directive. Our main objective is to test the effect of PPP induced protest votes on welfare measures for lost passive use value using different treatment procedures. We argue for a more reliable and defensible indicator of willingness to pay (WTP) in environmental liability litigation cases than current standard removal practices in cases where protest votes affect sample representativeness. Analyzing the impact of PPP-based protest response on WTP values with the help of a Full Information Maximum Likelihood sample selection model, a significant correlation is found between the decision to participate in the CV market and the WTP bids. Self-censoring biases average WTP and is correlated with factors such as respondent use of the resource and disposition towards its future protection. Simply removing protest response from the sample is indefensible and results in a biased estimation of WTP.     

Marginal WTP and Distance Decay: The Role of ‘Protest’ and ‘True Zero’ Responses in the Economic Valuation of Recreational Water Quality

We evaluate the sensitivity of distance decay in individuals’ stated willingness to pay (WTP) for water quality improvements in eutrophied lakes. We extend the standard model of contingent valuation (CV) by allowing individuals to adopt a sequential evaluation process consisting of two decision stages. In the first stage respondents decide whether they are ‘protesters’, have a WTP   \(=\)   ‘true zero’ or a \(\hbox {WTP}>0\) . Conditioned on a strictly positive WTP, we use Lee’s selectivity-corrected model to determine the magnitude of their WTP in the second stage. Using CV survey data from Norway we find significant distance decay in the first stage classification of respondents as ‘protesters’, ‘true zero’ WTP, or positive WTP. In the second stage model for positive WTP responses, we find little or no significant relationships when correcting for selection. Results suggest that previous findings of significant distance decay in contingent valuation of lake and river water in Europe may be driven by the definition of ‘protest’ and ‘true zero’ respondents. We find that WTP for water quality may be more useful as a qualitative indicator of political support for user financed water quality measures, than as a cardinal measure of marginal utility of water quality improvements.     

Choosing Between Internet and Mail Survey Modes for Choice Experiment Surveys Considering Non-Market Goods

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.     

Do protest responses to a contingent valuation question and a choice experiment differ?

It is suggested that the number of protest responses in stated preference surveys depends, inter alia, on the valuation method used. Choice Experiments (CE) are said to generate a lower number of protest responses than Contingent Valuation (CV). However, no comparison of both methods with respect to protest responses has been conducted to date. We used both CE and CV in a survey on forest biodiversity in two German regions. Protest beliefs were measured for all respondents irrespective of whether they were willing to pay or not. The results show no clear pattern of differences between CE and CV regarding protest beliefs and protest responses. Using an attitude scale based on respondents’ protest beliefs, we see a significant negative effect of this attitude on willingness to pay in both methods. However, in one of the two study regions, the effect is weaker in CE than in CV.      

Economic valuation of habitat defragmentation: A study of the Veluwe, the Netherlands

This paper offers an economic value assessment of a nature protection programme in the Veluwe, the Netherlands. This programme involves two defragmentation scenarios: the first scenario connects the central part of the Veluwe with river forelands in a north-eastern direction (i.e. the meadows of the IJssel river), while the second scenario is focussed on defragmentation in a south-western direction (i.e. the meadows of the Rhine river). The valuation is based on a questionnaire that was administered during face-to-face interviews in the area and through the Internet. We employ a contingent valuation approach to assess the respondents' willingness to pay for the realisation of the defragmentation scenarios. It appears that the mean willingness to pay (WTP) for the two defragmentation scenarios is € 162.2 (lognormal distribution) per respondent. Because the Veluwe is considered a nature park of national importance, we performed an aggregation of individual WTP estimates over Dutch households. With the resulting aggregate estimates we can compare the total costs and benefits of the two scenarios for habitat defragmentation in the Veluwe. In addition, we test whether respondents value the two scenarios equally. We also check whether the methods of data collection (face-to-face interviews and Internet questionnaires) have distinct influences on the stated WTP responses.     

Willingness to Pay and Sensitivity to Time Framing: A Theoretical Analysis and an Application on Car Safety

Stated preference (SP) surveys attempt to obtain monetary values for non-market goods that reflect individuals’ “true” preferences. Numerous empirical studies suggest that monetary values from SP studies are sensitive to survey design and so may not reflect respondents’ true preferences. This study examines the effect of time framing on respondents’ willingness to pay (WTP) for car safety. We explore how WTP per unit risk reduction depends on the time period over which respondents pay and face reduced risk in a theoretical model and by using data from a Swedish contingent valuation survey. Our theoretical model predicts the effect to be nontrivial in many scenarios used in empirical applications. In our empirical analysis we examine the sensitivity of WTP to an annual and a monthly scenario. Our theoretical model predicts the effect from the time framing to be negligible, but the empirical estimates from the annual scenario are about 70 % higher than estimates from the monthly scenario.     

The Effect of Protest Votes on the Estimates of WTP for Use Values of Recreational Sites

Contingent valuation studies are often characterized by a considerable number of protest responses, which may cause selectivity bias on the final estimates for WTP. Sample selection models can detect and – if necessary – correct selectivity bias. In economic applications where the relevant dependent variable is continuous, sample selection models are generally estimated using Heckman's 2-step method rather than the FIML estimator. Either method has its own drawback: computational complexity for the FIML method, susceptibility to collinearity problems for the 2-step method. Using data on valuation of forest resources for recreational use, we analyse the performance of the two estimators. In this application, given the presence of some collinearity, the FIML is preferred to the 2-step method. A procedure is outlined to deal with selectivity problems in similar settings.     

Are Internet surveys an alternative to face-to-face interviews in contingent valuation?

Internet is an increasingly popular data collection mode for stated preference research in environmental economics. However, little is known about how this survey mode may influence data quality and welfare estimates. As part of a national contingent valuation (CV) survey estimating willingness to pay (WTP) for biodiversity protection plans, we assign two groups of respondents either to an Internet or face-to-face (in-home) interview mode. Our design aims to better isolate measurement effects from sample composition effects by drawing both samples from the same sample frame. We find little evidence of social desirability bias in the interview setting or satisficing (shortcutting the response process) in the Internet survey. The share of “don't knows”, zeros and protest responses to the WTP question with a payment card is very similar between modes and equality of mean WTP cannot be rejected. Results are fairly encouraging for the use of Internet in CV as stated preferences do not seem to be significantly different or biased compared to face-to-face interviews.     

Keeping up appearances: Motivations for socially desirable responding in contingent valuation interviews

The tendency to give socially desirable rather than true statements of willingness to pay (WTP) is an often reported form of bias in contingent valuation surveys. While previous research on this bias has exclusively focused on the detection of mode effects, the present study directly assesses a respondent's motivation to state WTP in a socially desirable manner. This study tests the effect of three theoretical motivations for socially desirable responding on WTP responses: A general need for social approval, a perceived social norm calling for a high contribution and perceived lack of anonymity of the interview situation. Questions for the empirical assessment of these factors are developed.Results of a valuation study in Southwest China show differing and independent impacts of these factors. While there is no effect of perceived anonymity, need for social approval biases WTP responses upwards but does not influence the general decision to state a positive WTP. It also turns out that rather the fear of losing social status than the striving for higher social approval is the main driver of this bias. Respondents perceiving a social norm for high WTP are more likely to state a positive WTP, but the specific amount is not affected.     

Trust, Responsibility and the Interpretation of Contingent Valuation Results

Responses to contingent valuation questionnaires are contingent on respondent perceptions of trust and responsibility regarding aspects of the scenario presented to them. These issues can influence CV responses in several ways, with the net effect on WTP estimates depending on the relative prevalence of the different opposing effects in a given application. Whether such effects are to be considered biases, to be removed where possible, depends on the notion of validity one adopts. Whilst issues of trust and responsibility may pose little threat to predictive notions of validity, they are more problematic from a surplus validity, cost-benefit, perspective. Further discussion of the pros and cons of different validity notions for contingent valuation is required.     

On the contingent valuation of mortality risk reduction in developing countries

Using the contingent valuation method in developing countries to value mortality risk reduction is particularly challenging because of the low level education of the respondents. In this article, we investigate whether some brief training regarding probability and risk concepts has any significant effect on the willingness-to-pay (WTP) responses. We elicit individuals’ risk perceptions by providing information on age specific mortality risks and find that people on average overestimate the mortality risk at younger ages and underestimate it at older ages. Our results indicate a significantly higher WTP for the trained sub-sample and WTP is sensitive to the magnitude of risk reduction for both the sub-samples.     

Respondent direct experience and contingent willingness to pay for new commodities: a switching endogenous interval regression analysis

Most environmental economists argue that direct experience with the good being valuated, or with similar goods, is a precondition for providing valid willingness to pay (WTP) responses to contingent valuation questions. Two questions are posed in this article. The first is whether previous use experience of a resource (Séné nature reserve) similar to that being valuated (future nature reserves) and located in the same geographical area (Gulf of Morbihan) impacts on WTP. The second is whether accounting for the endogeneity of direct experience matters in the estimation of WTP. We find that respondents who have not experienced the Séné nature reserve provide value estimates that are statistically comparable to that of respondents who have experienced it. Our assumption is that respondents have acquired sufficient and adequate experience of future nature reserves from the questionnaire that experience obtained by experiencing the Séné nature reserve was not necessary for making a valid value formulation. Hence, aggregation of WTP estimates to obtain a total valuation of the future nature reserves is reasonable over the full target population. In addition, our results show that direct experience is endogenously determined; but controlling for the endogeneity has a marginal effect on WTP estimates.     

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.     

Reducing protest responses by deliberative monetary valuation: Improving the validity of biodiversity valuation

This paper focuses on examining the validity of biodiversity valuation methodologies. The results of a group deliberation technique (deliberative monetary valuation) are compared to those derived from a contingent valuation (CV) survey using the same environmental topic. Evidence is here presented that DMV can address some of the limitations of CV; namely a prevalence for lexicographic preference ordering due to psychological reasons and the lack of a priori or well-formed preferences. Both of these methodological shortcomings can result in protest responses which decrease the external validity of results. It is common environmental valuation methodology practice to exclude protest responses from the analysis on the grounds that they are illegitimate choices, thus the sample and consequently the environmental valuation analysis may become less representative of the population. An advantage of the DMV methodology is that it was found to significantly reduce the rate of protest responses to less than half (from 29% to 13%). Furthermore, DMV significantly increased the proportion of positive bids but not the amounts contributed. In relation to preference formation issues, we suggest rethinking the current practice of the DMV method, and propose dedicating the entire initial discussion session to introducing the good outside of a valuation context.