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.      

Improving the Performance of Contingent Valuation Studies in Developing Countries

This paper discusses three main reasons why so many of the contingentvaluation studies conducted in developing countries are so bad. First,the contingent valuation surveys themselves are often poorly administeredand executed. Second, contingent valuation scenarios are often very poorlycrafted. Third, few CV studies conducted in developing countries aredesigned to test whether some of the key assumptions that the researchermade were the right ones, and whether the results are robust with respectto simple variations in research design and survey method. The paper concludesthat research on stated preference methods in developing countries iscritically important to the successful implementation of these methodsbecause (1) there is no empirical evidence to suggest that rapid,”streamlined” CV surveys yield reliable, accurate results, and (2)there is a significant risk that the current push for cheaper, simplerCV studies could discredit the methodology itself. Moreover, the policydebates to which CV researchers are asked to contribute are often oftremendous importance to the well-being of households in developingcountries. Because the costs of policy mistakes can prove tragic, itis critical that VC researchers push for excellence in this researchenterprise and that funding agencies think more carefully about thevalue of policy-relevant information in the fields in which thecontingent valuation method is being used to study household preferencesand behavior (e.g., water and sanitation services, urban air pollution,soil erosion, deforestation, biodiversity, watershed management,ecosystem valuation, vaccines for the poor).     

Application of Sample Selection Model to Double-Bounded Dichotomous Choice Contingent Valuation Studies

Modeling households' behavior with the data from a contingentvaluation (CV) survey is often complicated by samplenon-response, which can cause non-response bias and sampleselection bias, leading to inconsistent parameter estimates and adistorted mean willingness-to-pay estimate. This paper reportsthe results of empirical tests for both biases using householdsurvey data in which the double-bounded dichotomous choice CVquestion involved the benefit of a tap water quality improvementpolicy in Korea. No non-response bias, but sample selection bias,is detected in the sample. To correct for sample selection bias,a sample selection model is employed. The authors also discusshow failure to correct for bias may distort aggregate benefitestimates.     

Minimising Payment Vehicle Bias in Contingent Valuation Studies

The payment vehicle is a crucial element inapplications of the contingent valuation methodbecause it provides the context for payment. However,in many countries a relative unfamiliarity with theuse of tax levies and referenda can affect theplausibility of payment vehicles and lead to paymentvehicle bias. The most commonly used approach fordetermining whether payment bias exists is to usetests of convergent validity. It is demonstrated thatsimple tests of convergent validity can be ineffectivein diagnosing the existence of payment vehicle bias.Payment vehicle bias is found to occur because ofdifferences in the coverage of payment vehicles anddoubts about payment being one-off. When respondentsare found to be protesting against a particularpayment vehicle, the current state of the art approachis to delete them from the sample. In this paper analternative approach that relies on the recoding ofprotest responses is proposed.     

Construct Validity of Dichotomous and Polychotomous Choice Contingent Valuation Questions

In this note we conduct construct validity tests for dichotomous choice (DC) and polychotomous choice (PC) contingent valuation questions. Contrary to previous results, we find that DC and PC estimates of willingness to pay are theoretically valid, convergent valid, and similar in terms of statistical precision. Similar to previous results, PC respondents are less sensitive to information than DC respondents. We conclude that DC and PC valuation questions are construct valid for this study. Sequential PC valuation questions could be used in studies where obtaining information about the certainty or intensity of respondent preferences would be useful.     

Addressing Negative Willingness to Pay in Dichotomous Choice Contingent Valuation

This paper has four purposes. First, we outline the controversy surroundingthe issue of negative willingness to pay (WTP)in contingent valuation (CV) studies. Second,we use Monte Carlo simulation to examine theperformance of alternative distributionalassumptions in estimating WTP in the presenceof varying proportions of the populationholding negative WTP values. We focus ondichotomous choice CV (DC-CV), where negativeWTP values may be especially difficult todetect. Third, we extend the simulation toinvestigate the performance of the mixturemodels that have recently been proposed forhandling/identifying non-positive WTP values. Fourth, we extend the simulation to investigatethe performance of the nonparametric lowerbound Turnbull approach. Results indicate thatthe relative performance of the DC-CV modelingalternatives evaluated here, which assumepositive WTP, varies across the simulationsetting (e.g., proportion of negative WTP); butnone can be said to reasonably ``solve' theproblem ex post. This underscores theimportance of ex ante efforts to identify ifnegative WTP is likely to be prominent in agiven valuation setting. In such cases,appropriately handling negative WTP must beaddressed through ex ante survey design andmodeling choices that allow negative WTP.     

Bid Design Effects in Multiple Bounded Discrete Choice Contingent Valuation

A potential concern in multiple bounded discrete choice contingent valuation surveys – where the respondent is asked to express voting certainty, rather than a simple yes or no, on a large number of payment amounts (bids) – is whether responses are influenced by the particular position of bids in the bid-voting panel rather than solely on the respondents willingness to pay (WTP). For instance, respondents may systematically state they would pay the first few bid amounts and not pay all subsequent bids – regardless of the actual dollar values. Such systematic bid design effects would suggest that this method does not provide a valid measure of WTP. Using a split-sample survey, we compare responses to three different bid arrays that have an identical minimum bid, maximum bid, and number of bids. Using nonparametric estimation techniques, we find that estimated WTP distributions and corresponding welfare measures are not statistically different across survey samples.     

A Learning Design for Reducing Hypothetical Bias in the Contingent Valuation Method

Over the last few years a great deal of research has focussed on hypothetical bias in value estimates obtained with the contingent valuation (CV) method and on means for ameliorating if not eliminating such bias. To date, efforts to eliminate hypothetical bias have relied on calibration techniques or on word-smithing of one kind or another to induce subjects to provide responses to hypothetical questions that mimic responses made by subjects facing actual payments in the valuation experiment. This paper introduces a different approach for eliminating hypothetical bias. A design for a CV survey format is presented which provides subjects with the opportunity to learn how the CV institution works. Sequential referenda are conducted where respondents gain experience in CV settings by participating in both hypothetical and real referenda. The logic of this Learning Design is a straightforward application of the trials process used in experimental economics. We demonstrate that the Learning Design is effective in eliminating hypothetical bias in surveys concerning donations to two different public goods.     

Preferences in the Future

Environmental economics has been much occupied with the discount rate, which is the value of future costs and benefits relative to present costsor benefits. But at least as important is the question of whatshould be discounted, that is, what the value of those future environmentalbenefits is to future generations. This paper analyzes the role for futurepreferences and discusses the state of knowledge. I argue that theappropriate discount rate is the market one, and that the real problemis determining future willingness-to-pay. This approach makes clearerthe connection between discounting and the valuation debate.This paper focuses on two features that have been prominent in that debate:existence value and reference dependence. I argue that thereis a vital connection between the two constructs and that this link yieldsimportant implications for future willingness-to-pay.     

Environmental Valuation – To Use or Not to Use? A Comparative Study of the United States and Europe

Valuation methods have been used for five main purposes in environmental decision-making. Cost–benefit analysis (CBA) of projects, CBA of new regulations, natural resource damage assessment, environmental costing, and environmental accounting. The relatively lower importance attached to economic efficiency in environmental decision-making in most European countries compared to the U.S.A., both legally and in practice, might account for our general finding that there are very few valuation studies in Europe which have served as a decisive basis for environmental policy and regulations. However, with EU's goal to establish environmentally adjusted national accounts and to apply CBA to environmental policy and regulations, time seems ripe for an increased use of valuation techniques in Europe.     

Problems in valuing the benefits of biodiversity protection

This paper considers two problems in valuing the benefits of biodiversity protection. These are, firstly, that preferences for biodiversity protection may be lexicographic rather than utilitarian. The more individuals for whom this is true, the less is cost-benefit analysis validated as a means of decision making for biodiversity protection, since lexicographic preferences are incompatible with the Kaldor-Hicks Compensation Test. Secondly, people may be poorly informed about the meaning of biodiversity, complicating the use of contingent valuation as a means of measuring preservation benefits. This paper first discusses the meaning of biodiversity, and trends in diversity over time. We offer some empirical evidence with regard to lexicographic preferences; consider the implications of having poorly-informed consumers; and then report the results of a contingent valuation study of biodiversity protection with varying levels of information. We find that willingness to pay for biodiversity protection increases with the level of information provided.We thank David Pearce, participants at a seminar at University College London, and two referees for comments on earlier versions of this paper.     

Incorporating Discontinuous Preferences into the Analysis of Discrete Choice Experiments

Data from a discrete choice experiment on improvements of rural landscape attributes are used to investigate the implications of discontinuous preferences on willingness to pay estimates. Using a multinomial error component logit model, we explore differences in scale and unexplained variance between respondents with discontinuous and continuous preferences and condition taste intensities on whether or not each attribute was considered by the respondent during the evaluation of alternatives. Results suggest that significant improvements in model performance can be achieved when discontinuous preferences are accommodated in the econometric specification, and that the magnitude and robustness of the willingness to pay estimates are sensitive to discontinuous preferences.     

CVM评估生态服务价值的经济有效性和可靠性理论述评

意愿价值法(CVM)以新古典需求理论为基础,构造假想市场使生态服务价值的评估成为可能。但在应用中产生各种不符合经济理论预期的经济"异常"现象,使其有效性和可靠性受到广泛质疑。本文系统梳理了国际上经济、生态、社会等领域学者对"异常"现象的理论解释与争论,阐明了CVM的应用必须考虑评估对象的性质、所处区域的社会制度条件、市场化程度等因素,并指出:要在我国推广应用CVM,必须结合我国转型经济特殊阶段的社会条件对其有效性与可靠性进行深入的理论探讨。     

Using Non Market Valuation to Inform the Choice Between Permits and Fees in Environmental Regulation

The purpose of this short note is to open an exploration regarding the use of non market valuation to help guide the selection of economically efficient pollution control instruments. As long as non market valuation techniques can correctly estimate the slope of the marginal benefit of abatement curve, this information along with engineering cost estimates of the unit costs or slope of the marginal abatement cost will provide useful information to policy makers in choosing between fees and permits. An illustrative review of the literature suggests that both stated and revealed preference methods have estimated slopes of marginal benefit functions for reducing several pollutants. To investigate the efficiency of permits versus fees, an illustrative review of corresponding marginal abatement costs is also made. For air pollutants affecting visibility, the slope of the marginal benefit curve is far greater than the slope of the marginal abatement costs, suggesting permits as the efficient instrument. For nitrates in groundwater used for drinking, the marginal benefit curve is flatter than the rather steep marginal abatement cost, suggesting fees/taxes would be a more efficient economic instrument. We hope this note stimulates more emphasis in non market valuation on estimating the slope of the marginal benefit function to enhance environmental economists ability to make policy recommendations regarding the choice of pollution instruments for specific pollutants.      

‘Adopt a Hypothetical Pup’: A Count Data Approach to the Valuation of Wildlife

The willingness to pay (WTP) for a coyote conservation program is estimated using a novel payment-vehicle, based on how many ‚problem’ coyotes respondents would be willing to sponsor for a year. This hypothetical scenario mimics an increasingly popular type of actual market. Data from a phone survey conducted in Prince Edward Island are analyzed using count data models that consider different processes explaining zero responses and the level of positive responses. This is particularly important in the case of coyotes, often regarded as an economic bad. Estimates of WTP per coyote per year around $18–$22 and annual WTP per contributor of about $46–$57 are obtained.      

Natural resource valuation with a tribal perspective: a case study of the Penobscot Nation

The unique settings of tribal lands and preferences of tribal members can complicate the effective application of standard natural resource use valuation tools within these tribal settings. We present a study which utilised referendum format contingent valuation methods to value foregone tribal use of the dioxin-contaminated Penobscot River in Maine. The Penobscot Nation’s prior experience in using referendums to evaluate cash settlement offers provides a unique setting for this application. The valuation responses pass a scope test and are consistent with a priori expectations of economic theory as well as individual attitudes and beliefs. Implicit discount rates based on the valuation of two clean-up periods are plausible. The response model indicates that cultural motives are a significant basis of foregone use values. While each tribal setting presents unique characteristics and challenges, the presented application demonstrates how carefully applied standard valuation tools, when appropriately designed to account for and incorporate tribal history, settings, and perspective, can yield defensible estimates of resource valuation.     

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.     

Preferences with and without prices - does the price attribute affect behavior in stated preference surveys?

The experimental as well as the non-market valuation literature include several examples of how an introduced price can affect behavior in otherwise not expected ways. It has become standard to include a price vector as an attribute in choice experiments, something that enables us to estimate a marginal willingness to pay for other attributes. We test the impact on preferences by an inclusion of a price in a choice experiment. Preferences are affected, as might be expected. However, also the relative ranking of individual attributes is affected.