Does don't know mean no? Analysis of 'don't know' responses in dichotomous choice contingent valuation questions

The ‘don't know’ response option in contingent valuation dichotomous choice questions is analysed using data from both willingness to pay and willingness to accept studies. An empirical analysis is conducted to determine whether respondents are stating a response similar to yes or no responses or a middle response. It is found that don't know responses are similar to no responses in the willingness to pay study. In the willingness to accept study, it is found that the ‘don't know’ responses are similar to a middle response. It is further suggested that researchers consider calculating ambivalence bounds when a don't know response is a middle response.     

Willingness to pay for a Green Energy program: A comparison of ex-ante and ex-post hypothetical bias mitigation approaches

The most persistently troubling empirical result in the contingent valuation method literature is the tendency for hypothetical willingness to pay to overestimate real willingness to pay. Two approaches, ex-ante and ex-post, have been developed to mitigate or eliminate the overstatement of hypothetical willingness to pay. The ex-ante approach addresses hypothetical bias in the survey design stage while the ex-post approach addresses hypothetical bias with follow-up questions to the hypothetical willingness to pay question. We find that willingness to pay estimates are similar when either the ex-ante or ex-post approach are employed. Our results suggest that the approaches should be considered as complements and not substitutes. Employing both approaches to mitigate hypothetical bias we estimate that the annual benefits of the regional amenities associated with a Green Energy program in North Carolina are $186 million.     

THE ECONOMIC VALUE OF PREVENTING RESPIRATORY AND CARDIOVASCULAR HOSPITALIZATIONS

This article provides estimates of the economic benefits of reducing respiratory and cardiovascular hospitalizations based on cost of illness and willingness to pay. The willingness-to-pay estimates indicate that individuals value prevention of a five-day hospitalization event at an average of approximately $2,400. Average total costs of illness per hospitalization are $22,000–39,000. A comprehensive cost-of-illness estimate that includes value of time losses for the hospitalization and at-home recovery periods provides a close approximation of total costs borne by third parties plus individual willingness to pay. Both exceed previous cost-of-illness estimates by about 10–25%. (JEL D61, I18, Q25 )     

A comparison of contingent valuation method and random utility model estimates of the value of avoiding reductions in king mackerel bag limits

This paper estimates the value of king mackerel bag limit changes with both stated and revealed preference methods. The 1997 Marine Recreational Fishery Statistical Survey allows estimation of the value of avoiding bag limit reductions with the random utility model and the contingent valuation method. Using the contingent valuation method, the willingness to pay to avoid a one fish reduction in the bag limit is $2.45 per year. Using the random utility model, the willingness to pay to avoid a one fish reduction in the bag limit is $2.24 per trip and $7.71 for a two-month time period. Considering several methodological issues, the difference in willingness to pay between the stated and revealed preference methods is in the expected direction.     

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.     

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.     

WTP- and QALY-Based Approaches to Valuing Health for Policy: Common Ground and Disputed Territory

This paper discusses links between two approaches to the value of health: the willingness to pay approach of environmental economics and the quality-adjusted life year approach of health economics. The approaches are used in cost-benefit and cost-effectiveness analyses of health interventions. Despite fundamental differences in the decision contexts and conceptual foundations of the two approaches, in current practice they are likely to lead to similar policy decisions. The paper also shows how research on the quality-adjusted life year (QALY) can be used to fill in gaps in the willingness to pay literature. The paper sketches a simple model that shows how to ``QALY-fy the value of a statistical life;' i.e., how to combine QALY estimates with estimates of the value of a statistical life to estimate willingness to pay for morbidity risks.Presented at the workshop “Economic Valuation of Health for Environmental Policy: Assessing Alternative Approaches," March 18–19, 2002, Orlando, Florida. I thank Glenn Blomquist, Mark Dickie, John Mullahy, Gary Zarkin and two anonymous referees for useful comments. All remaining errors are my own responsibility.     

Conditional-logit Bayes estimators for consumer valuation of electric vehicle driving range

Range anxiety – consumers’ concerns about limited driving range – is generally considered an important barrier to the adoption of electric vehicles. If consumers cannot overcome these fears it is unlikely that they will consider purchasing an electric car. Hence, a successful introduction of low emission vehicles in the market requires a full understanding of consumer valuation of driving range. By analyzing experimental data on vehicle purchase decisions in California, I derive and study the statistical behavior of Bayes estimates that summarize consumer concerns toward limited driving range. These estimates are superior to marginal utilities as parameters of interest in a discrete demand model of vehicle choice. One of the empirical results is the posterior distribution of the willingness to pay for electric vehicles with improved batteries offering better driving range. Credible intervals for this willingness to pay, as well as both parametric and nonparametric heterogeneity distributions, are also analyzed.     

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.     

THE IMPACT OF BESTSELLER RANK ON DEMAND: EVIDENCE FROM THE APP MARKET*

This article uses daily data on the ranking by sales of the top 100 apps sold through Apple’s App Store to provide evidence of the causal impact of today’s bestseller rank information on tomorrow’s demand. The estimates indicate that the willingness to pay of consumers is about $4.50 greater for a top ranked app than for the same unranked app. The results also indicate that the effects of bestseller status on willingness to pay decline steeply with rank at the top ranks, but remain economically significant for the apps in the first half of the top 100 list.     

The willingness to pay for mortality risk reductions in Mongolia

This paper reports results from a stated preference survey designed to estimate the willingness to pay for mortality risk reductions in Ulaanbaatar, Mongolia. The survey includes both contemporaneous and latent risk reductions of a magnitude typically achievable through clean air policy. The study is one of a series of national studies designed to provide comparable estimates around the world. One goal of this series is to build a more solid bridge for benefits transfer between developed and developing countries. The survey was conducted in winter 2010. Estimates of willingness to pay passed external and internal scope tests. Study results imply a value of statistical life of approximately $500,000 (based on a purchasing power parity exchange rate) for a contemporaneous 5-in-10,000 annual risk reduction.     

Cost credibility and the stated preference analysis of public goods

Two recent stated preference studies include questions that explore participants’ beliefs regarding the cost amount stated in the valuation question in relation to the cost to them if the project were implemented. Results from these studies suggest that a significant proportion of people do not believe these stated cost amounts. This paper explores the implications of participants answering valuation questions that are not consistent with their beliefs regarding stated costs. As an example, the paper develops a response model for dichotomous choice stated preference questions. Participants gather project information through the stated preference experiment, form a prior distribution of costs, update the distribution of costs based on a survey's stated cost and then respond to the dichotomous choice stated preference question. The model suggests that participants will not generally respond truthfully in the sense that they may say no to a stated cost that is less than their willingness to pay for a project or yes to a stated cost that is more than their willingness to pay. While the model findings suggest potentially serious problems with stated preference estimation, the observed patterns of disbelief from the empirical studies result in downwardly biased estimates of mean willingness to pay.     

The Effect of Risk Context on the Value of a Statistical Life: a Bayesian Meta-model

This paper presents the first value of statistical life (VSL) meta-analysis that empirically estimates correction factors for ‘out of context’ benefits transfer (BT) purposes. In the field of mortality risk reductions elicited willingness to pay values in one risk context, say road safety, are frequently applied in other risk contexts like air pollution. However, differences in risk perception and the population at risk across contexts are likely to result in diverging VSL estimates. In a meta-analysis of 26 international stated preference studies, a Bayesian model is estimated regressing contingent values for mortality risk reductions, originating from three different risk contexts, on the characteristics of the risk reduction itself and additional variables characterizing the underlying studies. A willingness to pay (WTP) premium for mortality risk reductions in the air pollution and general mortality risk context relative to improving road safety is observed. Evaluated at the mean, road safety VSL estimates should be multiplied by a factor 1.8 before being applicable in the air pollution context. Moreover, in an illustrative BT exercise we find limited overlap in the set of context specific predictive VSL distributions. Consequently, ‘out of context’ BT results in a substantial over- or underestimation of the VSL.     

Mixed logit estimation of willingness to pay distributions: a comparison of models in preference and WTP space using data from a health-related choice experiment

Different approaches to modelling the distribution of WTP are compared using stated preference data on Tanzanian Clinical Officers’ job choices and mixed logit models. The standard approach of specifying the distributions of the coefficients and deriving WTP as the ratio of two coefficients (estimation in preference space) is compared to specifying the distributions for WTP directly at the estimation stage (estimation in WTP space). The models in preference space fit the data better than the corresponding models in WTP space although the difference between the best fitting models in the two estimation regimes is minimal. Moreover, the willingness to pay estimates derived from the preference space models turn out to be very high for many of the job attributes. The results suggest that sensitivity testing using a variety of model specifications, including estimation in WTP space, is recommended when using mixed logit models to estimate willingness to pay distributions.     

Temporal insensitivity of willingness to pay and implied discount rates

A number of studies have defined and tested the temporal sensitivity of willingness to pay to payment schemes and the resulting implied discount rates for environmental projects. We demonstrate that those studies have imposed restrictive assumptions on the structure of the willingness to pay function and the underlying decision process. We investigate the temporal sensitivity of willingness to pay using a new temporal willingness to pay function applied to a proposed oyster reef restoration program. We find that (1) holding the length of the project constant, the temporal willingness to pay for the project is the same across different payment schemes, (2) temporal willingness to pay does not vary significantly across projects of varying lengths, and (3) estimated discount rates are low relative to previous studies, but vary significantly across payment schemes and project lengths.     

城镇消费者对有机农产品的购买意愿分析——以有机大米消费为研究对象

基于对北京市、武汉市城镇消费者对有机大米的消费行为调查,分析了有机农产品溢价购买意愿和边际购买意愿。运用联合分析法研究发现,当前消费者对有机农产品的溢价购买意愿倾向比较低,但边际购买意愿较高,价格过高限制了有机农产品的推广。另外,消费者对有机农产品的认知水平、品牌因素对消费者购买意愿有着重要的影响作用。     

ECONOMICS OF THE "CRITICAL USE" OF METHYL BROMIDE UNDER THE MONTREAL PROTOCOL

We analyze the economics of granting temporary exceptions to the phaseout of methyl bromide (MeBr) under the Montreal Protocol on Substances that Deplete the Ozone Layer. The protocol allows such exceptions based on technical or economic "feasibility" through a critical use exemption (CUE) process. Data compiled under the protocol make it possible to set forth criteria for the exceptions based on estimation of the benefits of compliance in terms of "willingness to pay" to abate the externality, as well as costs to the users creating the externality. We estimate a political willingness to pay and show that market and supply effects would reduce losses to MeBr users below estimates of such losses provided in CUE nominations. This suggests that the phaseout of MeBr can proceed with considerably fewer CUEs than requested by the parties. (JEL Q1 , Q2 , Q3 , H8 )     

Combining stated and revealed choice research to simulate the neighbor effect: The case of hybrid-electric vehicles

According to intuition and theories of diffusion, consumer preferences develop along with technological change. However, most economic models designed for policy simulation unrealistically assume static preferences. To improve the behavioral realism of an energy–economy policy model, this study investigates the “neighbor effect,” where a new technology becomes more desirable as its adoption becomes more widespread in the market. We measure this effect as a change in aggregated willingness to pay under different levels of technology penetration. Focusing on hybrid-electric vehicles (HEVs), an online survey experiment collected stated preference (SP) data from 535 Canadian and 408 Californian vehicle owners under different hypothetical market conditions.Revealed preference (RP) data was collected from the same respondents by eliciting the year, make and model of recent vehicle purchases from regions with different degrees of HEV popularity: Canada with 0.17% new market share, and California with 3.0% new market share. We compare choice models estimated from RP data only with three joint SP–RP estimation techniques, each assigning a different weight to the influence of SP and RP data in coefficient estimates. Statistically, models allowing more RP influence outperform SP influenced models. However, results suggest that because the RP data in this study is afflicted by multicollinearity, techniques that allow more SP influence in the beta estimates while maintaining RP data for calibrating vehicle class constraints produce more realistic estimates of willingness to pay. Furthermore, SP influenced coefficient estimates also translate to more realistic behavioral parameters for CIMS, allowing more sensitivity to policy simulations.     

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.