Preference uncertainty in contingent valuation

In this paper, the results of empirical studies that applied two widely used methods - numerical certainty scale (NCS) and polychotmous choice (PC) - for estimating preference uncertainty adjusted willingness to pay (WTP) in contingent valuation (CV), are summarized. For this review, a number of conclusions are reached. First, there is a lack of consensus about which method is more appropriate for measuring preference uncertainty. Second, although preference uncertainty information has been found useful in detecting the incidence of hypothetical bias in CV studies, a consensus about a standard certainty threshold (or treatment mechanism) at which hypothetical behaviour converges to real behaviour is yet to emerge. Third, insufficient empirical evidence exists about the causal relationship between preference uncertainty scores and the theoretically expected explanatory variables. Finally, the preference uncertainty adjusted PC and NCS models fail to provide a consistent and more efficient welfare estimate compared to the conventional dichotomous choice certainty model.     

Ordering effects in contingent valuation surveys

This paper focuses on ordering effects in CVM surveys; how the expressed value of a particular good valued in a sequence of several goods depends on where in the sequence the good is valued. We use data from a Norwegian CVM survey focusing on WTP for a 50% reduction in air pollution from car traffic to test for the existence of ordering effects and to apply a test for internal consistency. We found considerable and significant ordering effects in our data, but were not able to reject the hypothesis of internal consistency. Based on our survey, we argue that ordering effects may be a result of rational choice. These effects are problematic if a sequential valuation procedure is applied to a simultaneous problem, and/or the respondents are given imperfect information about the decision problem.     

Benefits of participating in contingent valuation mail surveys and their effects on respondent behavior: a panel analysis

We investigated the “fringe benefits” of participating in contingent-valuation mail surveys and their effects on respondents' answers. A two-wave panel survey evaluating Japan's anti-global warming policies was conducted. One sample was randomly assigned to either of two survey treatment groups with different survey loads. Factor analyses of answers distinguished the survey fringe benefit factor from the environmental concern factor. The correlation between the two factors was smaller for the heavy load group than for the light load group. Estimations of structural equation models showed that survey participation became higher when the survey fringe benefit factor scored higher. This tendency was found regardless of the survey load level. Structural equation models did not confirm a positive correlation between the survey fringe benefit factor and the consistency of WTP answers across survey waves. However, a logistic regression of the answers from the heavy-load group revealed a positive correlation between the consistency of WTP answers and the level of “perception of the survey as a good cause,” which was highly correlated to the fringe benefit factor in the previous factor analyses. This positive relationship was not detected for the light-load group.     

The validity of the contingent valuation method: Perfect and regular embedding

This article deals with one aspect of the validity claim of the contingent valuation method, namely: to what extent does the method produce different values in situations for which economic theory claims different values. Two aspects of this validity test — perfect and regular embedding — were tested in a field experiment comprising six samples of the Dutch population. Perfect embedding occurs when the value for a specific good is similar to the value for a more inclusive good. Perfect embedding did not manifest itself in the experiment. Respondents considered a package of six goods as well as a package of two goods more valuable than one of these goods. It is argued that this supportive evidence of the method's validity claim occurred because the goods involved were well-defined. Regular embedding occurs when the same good receives a lower value if the value for it is inferred from the value for a more inclusive good rather than if that good is valued on its own. Regular embedding was only found when respondents were given the opportunity to value the inclusive good before valuing the specific good. Respondents who were given information on the inclusive good without valuing it did not state different values than respondents who were not given that information. It seems that respondents perceive an inclusive good as being relevant to their valuation decision only when they are asked to value it. Further research is necessary to shed more light on the underlying processes that may account for this.     

Joint estimation of contingent valuation survey responses

Hanemann's utility difference model for the dichotomous choice contingent valuation method is modified to account for interrelationships between responses to a set of contingent valuation questions. A nonlinear seemingly unrelated regression model is presented to jointly estimate the probit models and to derive WTP from the CV responses. The model is used to test and impose restrictions derived from economic theory on the utility difference model. Mean WTP estimates for three different types of changes in the quality of California deer hunting were uniformly lower for the joint response probit model compared to a set of independent probit models.     

A new valuation question: analysis of and insights from interval open-ended data in contingent valuation

This paper introduces a type of open-ended valuation question where respondents state their willingness to pay in the form of an interval rather than a point estimate. Allowing the response to be expressed as an interval has advantages compared to traditional valuation questions: it captures potential valuation uncertainty, facilitates interpretation of uncertainty and most importantly, provides a richer set of information about individuals’ preferences. Furthermore, an open-ended willingness to pay format has advantages if a survey is carried out in more than one country. Too little is known about valuation uncertainty to represent willingness to pay only as an exact value. Therefore, this value should be complemented by upper and lower boundary estimates. In this paper I present new methods for estimating these different values. The methods are illustrated with results from a survey concerning wild salmon in the Vindel River, northern Sweden. The results suggest that the upper and lower boundaries provide a kind of confidence interval for the willingness to pay, which is encouraging for estimating these values to characterise willingness to pay. The results also illustrate that some earlier criticism in the literature of open-ended questions does not apply to the question presented in this paper.     

Modelling unobserved heterogeneity in contingent valuation of health risks

Human preferences for alternative levels of health risks can be heterogeneous. In this paper a flexible distribution approach to model health values elicited with the dichotomous choice contingent valuation method is considered. Rigid parametric structures cannot model sample heterogeneity while imposing strong assumptions on the error distribution. A mixture of normal distributions is considered which can approximate arbitrary well any empirical distributions as the number of mixtures increases. The model is applied to data on willingness to pay for reducing the individual risk of an episode of respiratory illness. The mixture distribution model is compared with the rigid probit model using a Bayes factor test. The results show that the mixture modelling approach improves performance while allowing for the consideration of alternative groups of individuals with different preferences for health risks.     

Costing the traffic barrier effect: A contingent valuation survey

When considering the environmental damage caused by road traffic, one traditionally focuses attention on the consequences of accidents, or on the impact of air and noise pollution. This somewhat narrow definition should be enlarged to capture other, more psychological nuisances. The barrier effect created by heavily travelled streets belongs to this group of nuisances, rarely described and never estimated in monetary terms. It particularly affects children, the disabled and elderly people for whom the street becomes too large to cross. In a survey carried out at Neuchâtel, Switzerland, a contingent market was proposed to suppress the barrier effect around the city centre. A valuation function to predict the bids is estimated and used to infer the annual cost of the nuisance.     

Treating respondent uncertainty in contingent valuation: A comparison of empirical treatments

This research examines the impact of uncertainty on contingent valuation responses using (1) a survey of Canadian landowners about willingness to accept compensation for converting cropland to forestry and (2) a survey of Swedish residents about willingness to pay for forest conservation. Five approaches from the literature for incorporating respondent uncertainty are used and compared to the traditional random utility model with assumed certainty. The results indicate that incorporating uncertainty has the potential to increase fit, but could introduce additional variance. While some methods for uncertainty can be an improvement over traditional approaches, it is imperative to exercise caution when making systematic judgments about the effect of uncertainty on contingent valuation responses.     

The evaluation of river water quality improvements by the contingent valuation method

The results of an application of the Contingent Valuation Method (CVM) to the estimation of the recreational benefits which would result from improvements in river water quality are described. This case study is used as a basis to discuss the wider, generic issues in the application of the CVM: in particular, the problems of defining the population who benefit; the nature of the goods; why they benefit; and the questions of validity and reliability. A series of recommendations both as to appropriate methodological procedures to be adopted in CVM studies are given and as to areas where further theoretical and methodological research is required.     

Cognitive ability and scale bias in the contingent valuation method

This study investigates whether or not the scale bias found in contingent valuation (CVM) studies on mortality risk reductions is a result of cognitive constraints among respondents. Scale bias refers to insensitivity and non-near-proportionality of the respondents’ willingness to pay (WTP) to the size of the risk reduction. Two hundred Swedish students participated in an experiment in which their cognitive ability was tested before they took part in a CVM-study asking them about their WTP to reduce bus-mortality risk. The results imply that WTP answers from respondents with a higher cognitive ability are less flawed by scale bias.     

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.     

Correcting for the endogeneity of pro-environment behavioral choices in contingent valuation

In contingent valuation studies, observed behavioral choices often enter as independent variables in the willingness to pay function. However, these variables may be endogenously determined when the error term in the behavioral model is correlated with the error term in the willingness to pay model. We investigate the effects of correcting for the endogeneity of a variable, namely membership status in environmental organizations that proxies unobservable characteristics of the respondents. Jointly modeling the membership variable and the willingness to pay response yields an estimate for the effect of the former that contradicts previous findings but is intuitive and agrees with theoretical expectations.     

Effect of substitutes in contingent valuation for a private market good

Economic theory predicts a decrease in valuation as the availability of substitutes increases. This paper describes a contingent valuation (CV) survey that investigates the effect of substitutes on valuation of private market goods. Using an approach that compares willingness to pay (WTP) values elicited from a CV question that accounts for substitutes with WTP values elicited from a similar question without substitutes, we find that allowing for substitutes can moderate WTP values. For the item valued in this study, a hamburger sandwich, allowing for substitutes was associated with a reduction of from 10% to 16% in stated values.     

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.     

Identifying inconsistent responses in dichotomous choice contingent valuation with follow-up questions

We develop a new but simple non-parametric method to diagnose inconsistency in double-bounded contingent valuation questions in the presence of both perfect and imperfect correlation between initial and follow-up response distributions. The proposed method can identify inconsistency in iterative responses at each bid interval. We apply this method to data from five well-known double-bounded contingent valuation surveys. The predictions of our model match closely with parametric outcomes. Further, we find that the inconsistency patterns generally vary for different data sets and different bid intervals within data sets. Therefore no single behavioral model can explain all latent inconsistency patterns either within or across data sets. In addition, we examine the impact of inconsistency in responses on bias and efficiency of the double-bounded format in the absence of correction for inconsistency. We conclude that the commonly cited benefits of the double-bounded format hold only in the special case of nearly perfect consistency between initial and follow-up response distributions. Our method provides a simple tool researchers can use to determine the similarity in response distributions between the initial and follow-up responses and whether incorporating collected follow-up responses are likely to actually increase efficiency without introducing bias.     

The legal environment and corporate valuation: Evidence from cross-border takeovers

We examine the cumulative abnormal returns to U.S. targets, their foreign acquirers, and the target-acquirer portfolio in 181 successful cross-border tender offers during the period 1982–1991. We find that the incentive mechanisms created by the degree of shareholder-creditor rights protection and legal enforcement in the acquiring firm country can explain the observed variation in target, acquirer, and portfolio returns. We also find that foreign acquirers overpay for Delaware-incorporated targets. Our results are strengthened after controlling for deal-related effects addressed in the domestic mergers and cross-border investments literature.     

Starting point bias and respondent uncertainty in dichotomous choice contingent valuation surveys

In this article, we develop a dichotomous choice model with follow-up questions that describes the willingness to pay being uncertain in an interval. The initial response is subject to starting point bias. Our model provides an alternative interpretation of the starting point bias in the dichotomous choice valuation surveys. Using the Exxon Valdez survey, we show that, when uncertain, individuals tend to answer “yes”.     

Information acquisition in auctions: Sealed bids vs. open bids

This paper studies the incentives of a bidder to acquire information in an auction when her information acquisition decision is observed by the other bidders before bidding. Our results show that the sealed bid (second price) auction may induce more information acquisition about a common component of the value than the open (English) auction but less about the private component of the value. Moreover, we show that more information about the private value and less information about the common value may improve efficiency and revenue. Consequently, our results suggest new arguments in favor of the open auction.     

Willingness to pay for a clear night sky: use of the contingent valuation method

This article applies the Contingent Valuation Method (CVM) to the issue of night sky pollution. Light pollution decreases the ability to view a clear, unobstructed night sky. We administered a survey to the students of the Rochester Institute of Technology (RIT) to obtain estimates of Willingness To Pay (WTP) to improve night sky visibility and to prevent deterioration in visibility. This is the first CVM study that attempts to distinguish between these different WTPs. We find that students are willing to pay significantly more for a larger improvement in night sky conditions. We also find significant differences in WTP to improve versus prevent deterioration in night sky conditions.