Economic Valuation of Environmental Damages due to the Prestige Oil Spill in Spain

This paper presents a parametric and non-parametric analysis of data from a contingent valuation study (CVM) conducted to estimate environmental use and passive use losses due to the Prestige oil spill. This is the first CVM study conducted in Europe after a large oil spill. The CVM survey was implemented using in person interviews. Mean willingness to pay (WTP) values were computed with both, a parametric and non-parametric approach. Parametric WTP estimation indicates that respondents in the sample are willing to pay about 40.51 € per household to avoid a similar future oil spill in Spain. This implies that on average, the Spanish society places a value of the environmental losses caused by the Prestige oil spill around 574 € million. Non-parametric estimates are slightly higher at 58.08 € per household. WTP results are similar to those obtained in the Exxon Valdez study.     

A Semi-parametric Estimator of Willingness-to-pay Applied to Dichotomous Choice Contingent Valuation Data

The use of dichotomous choice questions (Are you willing to pay $x?) has been advocated as superior to open ended questions (What would you be willing to pay?) in contingent valuation studies of non‐market goods. A supplementary dichotomous choice question, raising or lowering the bid price depending on the initial response, gives increased precision. However, a problem with these methods is that identifying the mean willingness to pay (WTP) is more complex, and often conditional on making a distributional assumption. This paper will present a semi‐parametric method for estimating WTP without invoking any such assumptions, using the interval inherent in the double bounded format, and based on estimating the underlying hazard function for the distribution of WTP. An advantage of the approach over other non‐parametric methods is that it allows one to include respondent characteristics as determinants of the individual decisions, and does so within a computationally straightforward framework.     

A comparison of empirical models used to infer the willingness to pay in contingent valuation

The essence of the contingent valuation method consists of creating a hypothetical market where respondents are asked about their willingness to pay (WTP) for a non-market good. Different empirical models can be formulated to estimate the expected WTP of a sample of respondents and, then, through aggregation, the social valuation of the good is inferred.This paper outlines the relevance of the distributional assumptions when estimating mean WTP. Several parametric and non-parametric methods are discussed and applied to calculate the existence value of a natural space. Results show that WTP is extremely sensitive to the empirical model used.First version received: November 2002 / Final version received: January 2004     

The Value of Household Water Service Quality in Lahore,Pakistan

Most existing literature focuses on the benefits of establishing basic drinking water access for unserved populations, the extensive water supply margin. In contrast, this article examines the intensive margin—the benefits of improving water service to under-served households, a growing population in developing country cities. We use contingent valuation to estimate willingness to pay (WTP) for improved piped water quality and reductions in supply interruptions among a sample of 193 households in Lahore, Pakistan. The distribution of WTP is described using parametric and non-parametric models. Results indicate that households in Lahore are willing to pay about 7.50 to7.50 to 9 per month for piped water supply that is clean and drinkable directly from the tap—comparable to the monthly cost of in-home water treatment, and about three to four times the average monthly water bill for sample households using piped water. Estimates of WTP for reducing supply interruptions are both smaller and more difficult to interpret, since a significant fraction of the estimated WTP distribution for supply improvements is negative. All of our WTP estimates are well below 4% of monthly household income, the World Bank’s benchmark upper bound for affordable water service.     

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.     

The impact of behavioural risk-reduction interventions on willingness to pay to avoid sexually transmitted infections: a stated preference study of justice-involved youth

Risky health behaviours, such as smoking, drinking and risky sex, are substantial contributors to the U.S. morbidity rates and healthcare costs. While economic models typically regard preferences as stable, a growing literature suggests that information, including how it interacts with intentions and attitudes, plays an important role in unhealthy behaviours. Relatedly, a large health literature demonstrates that theory-based behavioural interventions can successfully change risky behaviour. This study uses the contingent valuation (CV) survey method to investigate the impact of behavioural interventions on a novel outcome measure: the willingness to pay (WTP) to avoid the consequences associated with risky behaviour. Using novel pre- and post-intervention data from Project MARS (Motivating Adolescents to Reduce Sexual Risk), this study estimates the impact of the intervention on elicited WTP to avoid sexually transmitted infections (STIs). It is found that after the intervention, participants’ elicited WTP to avoid STIs were significantly higher, and more sensitive to differences in infection severity. These results suggest that the intervention may affect risky sexual behaviour by changing the perceived value of avoiding the consequences of risky sexual behaviour. Additionally, these findings contribute to an ongoing debate regarding the construct validity of CV studies in health economics.     

Public Preferences for Hydrogen Buses: Comparing Interval Data, OLS and Quantile Regression Approaches

We use a quantile regression (QR) approach to analyse contingent valuation estimates of public willingness to pay (WTP) for the air and noise pollution reductions associated with the introduction of hydrogen buses in London. QR results show that variables that were not significant in interval regression or ordinary least squares regression become significant at certain quantiles along the WTP distribution. In addition, the determinants of WTP at the lower tail of the distribution differ from those at the higher end of the distribution. Our findings illustrate the usefulness of quantile regression methods for analysing contingent valuation data, enhancing our understanding of the determinants of willingness to pay.     

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.     

Are There Income Effects on Global Willingness to Pay for Biodiversity Conservation?

This paper is concerned with the empirical relationship between biodiversity conservation values and income. We use random effects panel models to examine the effects of income, and then GDP per capita, on willingness to pay for habitat and biodiversity conservation. In a meta-analysis, 145 Willingness To Pay estimates for biodiversity conservation where existence value plays a major role were collected from 46 contingent valuation studies across six continents. Other effects included in the meta-analysis were the study year; habitat type; continent; scope as presented to respondents; whether WTP bids were for preventing a deterioration or gaining an improvement in conservation, whether a specific species or specific habitat was protected; whether the questionnaire used a dichotomous choice or an open-ended format; distribution format; and the choice of payment vehicle. GDP per capita seemed to perform as well as an explanatory variable as respondent’s mean stated income, indicating that it is wealth in society as a whole which determines variations in WTP. Even if large variation, our main conclusion is, that the demand for biodiversity conservation rises with a nation’s wealth, but the income elasticity of willingness to pay is less than one.     

The effect of distance on willingness to pay values: a case study of wetlands and salmon in California

Most contingent valuation studies in the literature utilized a pre-determined geographic market area for their sample frame. In other words, they did not include variables that would measure the extent of the geographic areas over which to aggregate willingness to pay. These studies implicitly assumed that the effects of geographic distance were moot; an assumption that could have led to an understatement of the aggregate benefit values computed in these studies. The overall goal of this study was to determine if distance affects willingness to pay for public goods with large non-use values. The data used came from a contingent valuation study regarding the San Joaquin Valley, CA. Respondents were asked about their willingness to pay (WTP) for three proposed programs designed to reduce various environmental problems in the Valley. A logit model was used to examine the effects of geographic distance on respondents' willingness to pay for each of the three programs. Results indicate that distance affected WTP for two of the three programs (wetlands habitat and wildlife, and the wildlife contamination control programs). We calculate the underestimate in benefits if the geographic extent of the public good market is arbitrarily limited to one political jurisdiction.     

An alternative interpretation of multiple bounded WTP data—Certainty dependent payment card intervals

This paper analyzes the multiple bounded format, in which uncertainty is directly incorporated into the WTP question. A new approach for analyzing multiple bounded uncertainty data is presented. The intuition underlying the approach is that uncertain individuals would like to state their WTP as intervals rather than precise values and that the width of the intervals is determined by the degree of uncertainty. The approach is compared to the one applied in Welsh and Poe [Welsh, M., Poe, G.L., 1998. Elicitation effects in contingent valuation: comparisons to a multiple bounded discrete choice approach. Journal of Environmental Economics and Management 36, 170–185] which treats uncertainty by conditioning responses on specific verbal probability statements. We argue that the conditioning approach overestimates mean and median WTP and that conditioning WTP estimates on probability statements like “probably” and “unsure” make them “fuzzy”. To empirically compare the two approaches we use data from 2004 concerning implementation of a predator protection policy in Sweden. Our analysis show that the suggested approach: (1) is more intuitive; (2) better fits the data; (3) estimates mean and median WTP with better precision; (4) is less sensitive to distributional assumptions; and (5) it is better suited for policy analysis.     

Can unbiased be tighter? Assessment of methods to reduce the bias-variance trade-off in WTP estimation

This paper aims at verifying the claim, appeared in recent literature, that it is possible to control for response bias associated to the double bound elicitation method, while keeping gains in efficiency of the WTP estimates. Results from a Monte Carlo analysis lead, in general, to reject the claim; but when initial bids are not correctly chosen, the gains in efficiency are confirmed. An empirical application dealing with WTP estimation for drinking water quality improvements illustrates a case where a flexible modeling approach based on Copula distributions allows relevant gains with respect to the Single Bound estimator.     

The value of online banking to small and medium-sized enterprises: evidence from firms operating in the uae free trade zones

This study estimates the willingness to pay of small and medium-sized enterprises (SMEs) for a business online banking services. The estimation utilizes a contingent valuation method employing data from 400 SMEs in the United Arab Emirates free zones. An interval regression model is used to identify company characteristics affecting WTP. The results indicate an average WTP for online banking of $518.50 per month. Firms engaging in international trade value these services at least 10% more than those with only domestic operations. Other variables that significantly affect WTP include number of employees and the transportation cost of using traditional branch banking.     

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.     

The Economic Value of Air-Pollution-Related Health Risks in China: A Contingent Valuation Study

The economic value of preventing adverse health effects related to air pollution is estimated using contingent valuation in three diverse locations in China. Values are estimated for three health endpoints: cold, chronic bronchitis, and fatality. Alternative statistical models are tested to study their impact on estimated willingness to pay (WTP) and on the relationship between WTP and respondent characteristics. Using the official exchange rate, the sample-average median WTP to prevent an episode of cold ranges between US$3 and US$6, the WTP to prevent a statistical case of chronic bronchitis ranges between US$500 and US$1,000, and the value per statistical life ranges between US$4,000 and US$17,000. Estimated mean values are between two and thirteen times larger. Our estimates are between about 10 and 1,000 times smaller than estimates for the US and Taiwan using official exchange rates. Indoor air quality, measured for a subset of respondents, shows no consistent relationship with WTP.     

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.     

Exchange Rules and the Incentive Compatibility of Choice Experiments

The incentive properties of stated-preference surveys continue to be a central debate in the valuation of public goods. The majority of empirical studies have focused on incentive properties of contingent valuation questions in relation to situations where answers have monetary consequences. This research explores the incentive properties of repeated, attribute-based choice questions when subjects are provided with an explicit connection between choices and outcomes. Two market/provision-rules are investigated: a posted-price market and a plurality-rule vote. These two provision rules are contrasted to treatments in which no provision rule is discussed—subjects are simply asked to choose their preferred alternative. These three hypothetical choice treatments are compared with a binding choice treatment. While none of the public good treatments are theoretically incentive compatible, we include a comparison of hypothetical and binding choices for a private-good that is incentive compatible. The private good experiments indicate that marginal willingness to pay (WTP) estimates from the hypothetical treatment are larger, but not statistically different than corresponding estimates in the binding choice treatment. Results for the public good experiments indicate that marginal WTP estimates from the hypothetical treatments are much larger, and statistically different than corresponding estimates in the binding choice treatment. The bias is largest when no provision rule is discussed. The bias is reduced with the inclusion of a provision rule, but surprisingly, there was no difference across provision rule treatments. Overall, our results indicate that choice experiments involving a public good should include a provision rule to reduce bias, but the resulting marginal WTP estimates may still be more biased, on average, than those arising from contingent valuation survey formats.     

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.     

WILLINGNESS TO PAY FOR AIR QUALITY: THE CASE OF OUTDOOR EXERCISE

This study uses a contingent valuation (CV) survey to establish a sample of outdoor exercisers' willingness to pay (WTP) for ambient air quality improvements in East Baton Rouge parish, Louisiana. Estimated annual median and mean WTP values are £95 and £191, respectively, per person per year for assurance that ozone levels would not become "unhealthful" on any day. The survey informed respondents that in the prior year the local community experienced 14 days on which ozone levels exceeded federal standards. The study makes the strong assumptions that respondents believed they were "buying" 14 more healthy days and that WTP per day "bought" is constant. Given these assumptions, one can scale this WTP response to represent annual medians and means of approximately £7 and £14 per person per day, respectively. An econometric procedure for generalizing the community's annual WTP to avoid the 14 unhealthful days yields estimates ranging from £3.21 and £5.36 per person per healthy day, or between £12.4 and £20.6 million per year. The unit day estimates are comparable to CV and household production finction estimates of WTP in the Los Angeles basin, suggesting their usefulness for benefits transfer .