Preference Anomalies,Preference Elicitation and the Discovered Preference Hypothesis

There is wide-ranging evidence, much of it deriving from economics experiments, of ‘anomalies’ in behaviour that challenge standard preference theories. This paper explores the implications of these anomalies for preference elicitation methods. Because methods that are used to inform public policy, such as contingent valuation, are based on standard preference theories, their validity may be called into question by the anomaly data. However, on a new interpretation, these anomalies do not contradict standard theory but are errors in stated preference that can be expected to disappear as people become more experienced in relevant decision environments. We explore the evidence for this interpretation and what implications follow for preference elicitation methodology. JEL classifications: C91, D01, D60, D81, D83, H40     

Do People Always Pay Less Than They Say? Testbed Laboratory Experiments with IV and HG Values

Hypothetical bias is a long‐standing issue in stated preference and contingent valuation studies—people tend to overstate their preferences when they do not experience the real monetary consequences of their decision. This view, however, has been challenged by recent evidence based on the elicitation of induced values (IV) in the lab and homegrown (HG) demand function from different countries. This paper uses an experimental design to assess the extent and relevance of hypothetical bias in demand elicitation exercises for both induced (IV) and homegrown (HG) values. For testbed purpose, we use a classic second‐price auction to elicit preferences. Comparing the demand curve we elicit in both, hypothetical bias unambiguously (i) vanishes in an IV, private good context and (ii) persists in HG values elicitation context. This suggests hypothetical bias in preference elicitation appears to be driven by “preference formation” rather than “preference elicitation.” In addition, companion treatments highlight two sources of the discrepancy observed in the HG setting: the hypothetical context leads bidders to underestimate the constraints imposed by their budget limitations, whereas the real context creates pressure leading them to bid “zero” to opt out from the elicitation mechanism. As a result, there is a need for a demand elicitation procedure that helps subjects take the valuation exercise sincerely, but without putting extra pressure on them.     

Researching Preferences,Valuation and Hypothetical Bias

A number of recent papers in environmental economics have focused on the process of researching preferences – agents are uncertain about preferences but with effort may narrow their uncertainty. This issue has arisen in formulating bids in contingent valuation (CV) as well as the debate over the divergence between WTP and WTA. In the context of CV, it has been suggested that the hypothetical nature of the preference elicitation process biases responses. This paper provides both a theoretical model and experimental evidence to contribute to this debate. The model is a model of competitive bidding for a private good with two components that are particularly relevant to the debate. The first component is that bidders are unsure of their own value for the private good but may purchase information about their own value (researching preferences). The second component is that there is a probability that the auction is hypothetical – that the winning bidder will not get the private good and will not pay the winning bid. The experiment tests this theoretical model of bidding equilibrium and analyzes the effects of variations in the parameters (hypotheticalness, information costs and number of agents) on the endogenous variables (such as the proportion of bidders who become informed and the winning bid). Experimental results suggest that an increase in the hypotheticalness of an auction tends to decrease the likelihood that bidders pay for information on their valuation with an ambiguous effect on the winning bid.      

The Adding-Up Test in an Incentivized Value Elicitation Mechanism: The Role of the Income Effect

In the context of testing the construct validity of stated preference studies, some researchers advocate the use of an “adding-up test” designed to gauge whether elicited values are sufficiently sensitive to a change in the scope (i.e. size) of a good. Crucial to the applicability of this test in practice, which relies on endowing a subsample of respondents with a good free of charge, is that the income effects due to endowment are negligible. In this study, we apply the adding-up test in an experimental value elicitation format to examine the potential effect of endowment as part of the test design on the adding-up property of elicited values. The results show that the adding-up property can be affected by free provision of part of the bundle.     

A comparative study of environmental amenity valuations

The paper reports on a comparative study of direct and indirect approaches to valuing environmental amenities (i.e., public goods), specifically, air quality in terms of its human health effects. The application of three indirect valuation methods (via market goods) is reported here: the health production method, a consumer preferences (for nonmarket goods) model, and the cost of illness method. The first and second methods are (economic) behavior-based approaches where willingness to pay for an environmental good is derived by exploiting relationships in consumption between the public good and market good(s). The third method is based on a physical relationship—a dose-response function—between the environmental good and health. The direct valuation approach encompassed three contingent valuation elicitation formats: open-ended, modified iterative bidding game, and referenda-style binary choice. The application of all four methods was based on data from a survey of a large, stratified sample of households from the Haifa metropolitan area in northern Israel. The estimates of welfare change derived by the various methods are discussed and compared.     

Comparing continuous and discrete contingent valuation questions

This paper explores two commonly used methods to elicit an individual's willingness to pay (WTP) for a public good in contingent valuation studies. Currently, the most preferred method is the take-it-or-leave valuation question, or discrete valuation question (DVQ), where the respondent accepts or rejects a suggested cost for the good. The traditional method, the continuous valuation question (CVQ), simply asks an individual to state his WTP for the suggested change in the provision of a public good like cleaner air. We introduce a simple way to compare the results from these two methods. We also test the anchoring behavior suggested in the psychological literature on choice under uncertainty. The results do not support the anchoring hypothesis, but suggest the hypothesis that people perceive the two tested valuation questions differently.I would like to thank Prof. Glenn Harrison, University of South Carolina, Prof. P-O Johansson, Stockholm School of Economics, Prof. Jason Shogren, Iowa State University, and two referees for helpful comments. The usual disclaimer applies.     

The Worth of a Possum: Valuing Species with the Contingent Valuation Method

The focus of this paper is on methods of assessing the value peopleplace on the conservation of species for use in policy making. Of principalinterest is the relatively new methodology of contingent valuation, whichis a method for asking people directly about their preferences. The paperpresents an application of the contingent valuation method to theconservation of an endangered species in the State of Victoria, Australia.The results emphasise the importance of careful survey design,implementation and analysis as well as the precise definition of theenvironmental good being valued. Consequently, the contingent valuationmethod does provide information relevant to decision making processesbased on monetary economic considerations. Thus, in orthodox economicterms it makes sense to conserve species – but there are other moral andethical grounds for conserving species as well.     

A Bayesian Approach to Double Bounded Contingent Valuation

In this paper we propose a Bayesian approach to model double bounded contingent valuation data. The double bounded elicitation method is interpreted as a two tier iterated process in which the subject is allowed to have a second thought about his/her valuation for the environmental good. Prior information is modelled from the answers to the first dichotomous choice question. The model is Quasi-Bayesian (Q-B) in that the prior distribution refers to mean willingness to pay while the likelihood function refers to the proportions of a multinomial distribution. This model is applied to empirical data from a contingent valuation survey involving the valuation expressed by European tourists for access to natural areas in the Canary Islands. Results show that point estimate of consumer surplus computed with the Q-B model does not differ substantially from single bounded model estimation. In addition, double bounded seems to be quite robust to the choice of the prior model of willingness to pay responses. Comparison with open ended suggests that the Q-B model might be useful to control for strategic response and starting point biases.     

Linking forestry, sustainability and aesthetics

In forest planning, little research has been devoted towards examining how visual-impact assessment can improve the public acceptance of forest activities and augment forest sustainability. The objective of the present work is to review the methods of aesthetic assessment of forest landscapes, which will help the implementation of visual-impact assessment in sustainable forestry. From the numerous techniques of landscape evaluation that have been devised in recent years, the expert approach techniques have dominated in environmental management practices and the perception-based approach in research. The non-market economic valuation techniques are essentially trade-off methods and not aesthetic assessments by themselves. Revealed preference methods, such as hedonic-price, use actual market choices of individuals to get their preferences towards non-market attributes, and stated preference methods, such as contingent valuation method, rely on surveys to get directly the individual's willingness to pay for the non-market attributes. Psychophysical preference modelling is a popular quantitative holistic technique of landscape evaluation and if used in combination with indirect aesthetic evaluation methods might create new standards and protocols for techniques of objectively estimating public perception of aesthetic quality and thus to enhance social sustainability in forest space.     

Using contingent valuation to elicit public preferences for water fluoridation

The methods and results of a contingent valuation survey to elicit public preferences for water fluoridation are reported. The study demonstrates that not only is it important to acknowledge that there will be losers from the introduction of such a programme but that losers must be allowed to express a value for the magnitude of their perceived loss. Two methods of valuing this loss are explored. Conventional willingness to accept compensation questions are compared with questions in which losers are asked to state their willingness to pay to prevent their water being fluoridated. The results provide tentative support for asking willingness to pay to prevent questions instead of willingness to accept questions when evaluating certain types of public good. The issue of protest responses in contingent valuation surveys is also highlighted and discussed.     

Testing the Effectiveness of Certainty Scales,Cheap Talk,and Dissonance-Minimization in Reducing Hypothetical Bias in Contingent Valuation Studies

Stated preference methods such as contingent valuation and choice modeling are subject to various biases that may lead to differences between actual and hypothetical willingness to pay. Cheap talk, follow-up certainty scales, and dissonance minimization are three techniques for reducing this hypothetical bias. Cheap talk and certainty scales have received considerable attention in the literature, but dissonance minimization has not previously been experimentally tested. Using a four-way split sample design involving over 600 subjects, results from an actual referendum on provision of a quasi-public good were compared with three similar but contingent referenda employing the three bias-reducing techniques. Hypothetical bias was again present. Certainty scales, when properly calibrated, and dissonance minimization were found to be most effective in reducing the bias.     

Binary Choice Valuation Studies with Heteregeneous Preferences Regarding the Program Being Valued

We investigate the effect of respondents' heterogeneous preferences regarding the good to be valued in binary-choice contingent valuationstudies. This is especially important when the valuation options give rise to both highly negative and highly positive attitudes.The survey design employs questionnaires which include separate items for willingness to favorandwillingness to contribute in monetary terms to the provision of the good. In light of our analysis, eliciting respondents' differentpreferences for the project first, without monetary considerations, wouldimprove the WTP estimates as welfare measures. Our results alsosuggest that nonparametric estimation could offer another solution foraccounting for preference heterogeneity. Nonparametric estimation is less sensitive to those `no' responses which are in fact not intended toreflect the respondents' WTP as such but merely to express their dislikefor the good at issue.     

Anchors,endorsements, and preferences: A field experiment

This study investigates how access to political endorsements affects stated preferences for an environmental public good in Switzerland. We developed a contingent valuation survey questionnaire with two valuation questions, the first formulated as a (hypothetical) policy referendum, the second an open-ended WTP question. For the referendum question we solicited endorsements from a range of political parties and relevant interest groups. We then conducted a split-sample mail-survey experiment in which a table listing the endorsements was included with a subsample of the questionnaires. Access to the policy endorsements significantly affected the responses to the open-ended willingness-to-pay question.     

What Experimental Protocol Influence Disparities Between Actual and Hypothetical Stated Values?

Preferences elicited in hypothetical settings have recently come underscrutiny, causing estimates from the contingent valuation method to bechallenged due to perceived ``hypothetical bias.' Given that the receivedliterature derives value estimates using heterogeneous experimentaltechniques, understanding the effects of important design parameters onthe magnitude of hypothetical bias is invaluable. In this paper, we addressthis issue statistically by using a meta-analysis to examine data from 29experimental studies. Our empirical findings suggest that on averagesubjects overstate their preferences by a factor of about 3 in hypotheticalsettings, and that the degree of over-revelation is influenced by thedistinction between willingness-to-pay and willingness-to-accept, publicversus private goods, and several elicitation methods.     

Scale-perception bias in the valuation of environmental risks

The valuation of environmental risks is commonly approached with the utilization of stated preference methods such as contingent valuation. In these methods, money is utilized as the scale that reflects the individual's underlying utility function. However, this scale can vary across individuals due to different perceptions on what are the right or appropriate bounds for Willingness To Pay (WTP). In this article, we test for scale-perception bias and propose a correction method based on the utilization of anchoring vignettes that define different degrees of preference for the nonmarket good. The proposed method is applied to study the commonly found anomaly ‘probability neglect’, which is defined by the insensitivity to the probability levels in the valuation of environmental risks. The results show that probability neglect disappears when WTP responses are corrected for self-perception bias through the utilization of the anchoring vignettes approach.     

Referenda Under Oath

Herein we explore whether a solemn oath can eliminate hypothetical bias in a voting referenda, a popular elicitation mechanism promoted in non-market valuation exercises for its incentive compatibility properties. First, we reject the null hypothesis that a hypothetical bias does not exist. Second, we observe that people who sign an oath are significantly less likely to vote for the public good in a hypothetical referenda. We complement this evidence with a self-reported measure of honesty which confirms that the oath increases truthfulness in answers. This result opens interesting avenues for improving the elicitation of preferences in the lab and beyond.     

Preferences for environmental quality under uncertainty

Although the expected effects of environmental policies and interventions are rarely known with certainty, stated preference surveys rarely elicit preferences over uncertain environmental outcomes. This article presents empirical results challenging the view that ignoring such uncertainty during preference elicitation is of no consequence so long as people only care about final environmental states. We show that measured preferences for final environmental states, water quality in this case, depend on whether people choose between final states or between lotteries over final states. In contrast to the typical finding for monetary lotteries, we find significant under-weighting of low probability events related to water quality.     

Induced-Value Tests of Contingent Valuation Elicitation Mechanisms

Using an induced-value experimental design that varies whether values for a “good” are certain or uncertain and whether payment is real or hypothetical, this study investigates issues of demand revelation, hypothetical bias, and value uncertainty for four elicitation mechanisms used in contingent valuation surveys: dichotomous choice, dichotomous choice with follow-up certainty question, payment card, and multiple-bounded discrete choice. For all elicitation mechanisms, we find no evidence of hypothetical bias: voting decisions do not vary systematically when payment is hypothetical versus when it is real. Under all design conditions we find the fewest deviations between stated and induced values and the strongest evidence of demand revelation with dichotomous choice. Stated uncertainty in dichotomous choice follow-up and multiple-bounded discrete choice questions does correlate with uncertain induced values, but the signal is noisy. We discuss the implications of our findings for the design of contingent valuation surveys.     

Testing Temporal Reliability and Carry-over Effect: The Role of Correlated Responses in Test-retest Reliability Studies

Test-retest studies help establish the reliability of contingent valuation (CV) responses but must confront the problem that the initial response may influence subsequent responses, and thus weaken conclusions. We develop a model that tests the influence of heterogeneous preferences and previous responses. By estimating a model of sportfishing, we show that correlation between answers to a CV question is induced by heterogeneous preferences.     

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.