Contingent values as implicit contracts: estimating minimum legal willingness to pay for conservation of large carnivores in Sweden

Mean willingness-to-pay (WTP) based on multiple bounded, discrete choice responses from contingent valuation surveys are normally obtained using some kind of parametric estimator. This paper instead exploits the possibility to interpret the response to the discrete-choice question as an implicit contract between the researcher and the respondent, resulting in a minimum legal WTP (MLW) estimator. Never previously used in valuation literature, it is used in this paper to estimate the WTP for the preservation of large carnivores in Sweden, based on a large scale, national survey. Results show that MLW estimates only were 12–19% of the comparable parametric estimates. In keeping with other results in contingent valuation literature, we find that the MLW estimates are positively related to the educational level, income and the fraction of urban population, while negatively related to age. Among the advantages of the MLW estimator is its transparency as well as the fact that it rests on a contractual notion of WTP.      

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.     

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.     

A Meta-study Investigating the Sources of Protest Behaviour in Stated Preference Surveys

It is a well-known empirical finding that some percentage of respondents participating in Stated Preference surveys will not give responses that reflect their true preferences. One reason is protest behaviour. If the distribution of protest responses is not independent of respondent or survey characteristics, then simply expelling protesters from surveys can lead to sample selection bias. Furthermore, WTP estimates will not be comparable across surveys. This paper seeks to explore potential causes of protest behaviour through a meta-study based on full datasets from 38 different surveys. The objective of the study is to examine the effect of respondent specific variables as well as survey specific variables on protest behaviour. Our results suggest that some of the differences in WTP typically observed between different demographic groups, different elicitation formats and different question formats might actually be attributed to inherent differences in the propensity to protest. Our results indicate that the propensity for respondents to exhibit protest behaviour when asked a stated preference type valuation question depends on a number of specific factors, respondent specific as well as survey specific—knowledge which could be used in order to reduce protest behaviour.     

The total economic value of threatened, endangered and rare species: An updated meta-analysis

This paper updates a 1996 meta-analysis of studies using the Contingent Valuation Method (CVM) to value threatened, endangered and rare species published in this journal by Loomis and White. A variable for studies conducted in or after 1995 was added to the model to test if new studies are systematically different from old studies and identify which explanatory variables influencing willingness-to-pay (WTP) for these species have changed over time. Generally newer studies yielded higher WTP. Variables such as the change in the size of the species population, payment frequency, survey mode, response rate, type of respondent, type of species, and a new variable for whether a species is a ‘charismatic megafauna’ or not, whether the species has use and nonuse value versus nonuse value only and year of the study, were found to significantly influence WTP. This model is used in a benefit transfer example and a comparison of original study estimates and model estimates is made to compare its accuracy. The average within sample benefit transfer error was 34-45%.     

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.     

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.     

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.     

Enhanced Geospatial Validity for Meta-analysis and Environmental Benefit Transfer: An Application to Water Quality Improvements

Meta-regression models are commonly used within benefit transfer to estimate willingness to pay (WTP) for environmental quality improvements. Theory suggests that these estimates should be sensitive to geospatial factors including resource scale, market extent, and the availability of substitutes and complements. Valuation meta-regression models addressing the quantity of non-market commodities sometimes incorporate spatial variables that proxy for a subset of these effects. However, meta-analyses of WTP for environmental quality generally omit geospatial factors such as these, leading to benefit transfers that are invariant to these factors. This paper reports on a meta-regression model for water quality benefit transfer that incorporates spatially explicit factors predicted by theory to influence WTP. The metadata are drawn from stated preference studies that estimate per household WTP for water quality changes in United States water bodies, and combine primary study information with extensive geospatial data from external sources. Results find that geospatial variables are associated with significant WTP variations as predicted by theory, and that inclusion of these variables reduces transfer errors.     

Temporal stability of preferences and willingness to pay for natural areas in choice experiments: A test–retest

The main objective of this paper is to test the temporal stability of stated preferences and willingness to pay (WTP) values from a Choice Experiment (CE) in a test–retest. The same group of participants was asked the same choice tasks in an internet-based CE, conducted twice with a time interval of one year without interviewer interference. We examine choice consistency at individual choice task level and transferability of the underlying indirect utility function and associated WTP values. The results show that choices are consistent in 57 percent of the choice occasions. Comparison of the choice models over time shows that the estimated preference and scale parameters are significantly different, suggesting that choice behaviour changed between the two surveys. Differences between marginal WTP estimates for individual choice attributes are statistically significant only at the 10 percent level. However, we show that this can result in significantly different WTP values for policy scenarios. The instability of estimated mean WTP values for different policy scenarios asks for caution when including WTP values in cost-benefit analysis.     

Sensitivity of Willingness to Pay Estimates to the Level of Attributes in Discrete Choice Experiments

This paper considers issues raised in the application of discrete choice experiments (DCEs) to estimating willingness to pay (WTP). The main issue addressed is the sensitivity of WTP estimates to the level of attributes. A DCE, concerned with preferences for alternative cervical screening programmes, was carried out with women in the Tayside area of Scotland. A split sample design was employed in which respondents were divided into two groups. Each group received a discrete choice questionnaire that varied with respect to the levels of three of the six attributes. The price attribute was one of the attributes that varied across questionnaires. Whilst estimated coefficients were not significantly different across five of the six attributes included in the experiment, mean WTP estimates were significantly different for four of the five welfare estimates. However, from a policy point of view, such a difference may not be important. Consideration is also given to other general methodological and policy issues that are raised when using DCEs to estimate WTP. The findings suggest the need for further research into the design and application of DCEs as a method for estimating WTP.     

Willingness to Pay for Car Safety: Evidence from Sweden

This study estimates a marginal willingness to pay (WTP) function for a road-mortality risk reduction. Observed marginal WTP from the Swedish car market is used and found to be positively correlated with the baseline risk of the cars. No statistically significant relationships between examined owner attributes, e.g. wealth and background risk, and marginal WTP are found. When comparing the estimated monetary value of a non-marginal risk reduction derived from the integral of the marginal WTP-function with an estimate based on marginal WTP we find, in line with expectations, that the difference between the estimates is negligible for smaller risk reductions and small, 4–10%, also for relatively large risk reductions.      

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.     

Children’s health benefits of reducing environmental tobacco smoke exposure: evidence from parents who smoke

This paper uses data from the 1991 National Maternal and Infant Health Survey to estimate propositions derived from a model of intrahousehold allocation, wherein parents engage in a consumption activity (smoking) that produces own utility, while generating environmental tobacco smoke (ETS) that harms their children’s health. We find a statistically significant negative association between sample mothers‘ assessed health of their children and the children’s daily exposures to ETS. Mothers’ average annual willingness-to-pay (WTP) for a 1-hour-per-day reduction in child ETS exposure (about a 17% decrease in daily exposure) is about $150. WTP estimates for respondent mother and child health status further suggest that smoking mothers on average value their child’s health roughly 55% higher than their own health. Helpful comments and suggestions by Scott Atkinson, Donald Kenkel, and two anonymous referees are gratefully acknowledged. Marcy Agee and Stefanos Nastis provided valuable research assistance. Although the U.S. Environmental Protection Agency provided financial support through Grant#R82871601, the research has not been subjected to the Agency’s required peer and policy review and therefore does not necessarily reflect the views of the Agency     

Non-attendance and dual processing of common-metric attributes in choice analysis: a latent class specification

There is a growing literature that promotes the presence of process heterogeneity in the way that individuals evaluate packages of attributes in real or hypothetical markets and make choices. A centerpiece of current research is the identification of rules that individuals invoke when processing information in stated choice (SC) experiments. These rules may be heuristics used in everyday choice making as well as manifestations of ways of coping with the amount of information shown in choice experiment scenarios. In this paper, using the latent class framework, we define classes based on rules that recognise the non-attendance of one or more attributes, as well as on the addition and the parameter transfer of common-metric attributes. These processing strategies are postulated to be used in real markets as a form of cognitive rationalization. We use a SC data set, where car driving individuals choose between tolled and non-tolled routes, to translate this new evidence into a willingness to pay (WTP) for travel time savings, and contrast it with the results from a model specification in which all attributes are assumed to be attended to and are not added up with parameter preservation. We find that the WTP is significantly higher, on average, than the estimate obtained from the commonly used full relevance and attribute preservation specification.     

Popular Support for Climate Change Mitigation: Evidence from a General Population Mail Survey

Using a sample of 1,651 US households, we explore some determinants of willingness to pay (WTP) for climate change mitigation programs. Our mail survey had a relatively low response rate, so we first use several additional data sources to build a detailed sample selection model. This model uses features of the survey instrument, measures of geographic vulnerability to climate change, seasonality, the political mix in the county, attributes of the address or addressee, and a set of factor scores from an extensive factor analysis of all census tracts in the US. We estimate this model jointly with a model to explain climate policy preferences as a function of the domestic and international distribution of policy costs as well as the climate change impacts that each respondent believes will occur under a policy of business-as-usual. Despite statistically significant patterns of nonresponse, selectivity effects are minimal in this case. WTP for climate change mitigation is greater when the domestic incidence of mitigation costs is borne mostly through higher energy taxes. It is also greater when costs are understood to be shared internationally with other groups of countries, rather than being borne mostly by a country group including the US. People are generally more willing to pay for climate change mitigation if they believe that the harm caused by climate change impacts will be substantial, rather than just moderate. The assistance of former UCLA undergraduate students Ivka Adam, Tashi Ghale, Michelle Gogolewski, Vilija Gulbinas, and Lindy Olsson was essential to survey development and administration. This paper is based upon work supported in part by the National Science Foundation under Grant No. 9818875 to UCLA, with additional support from the Raymond F. Mikesell Foundation at the University of Oregon. Any opinions, findings, and conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of either the National Science Foundation or ICF International.     

HETEROGENEITY IN WILLINGNESS‐TO‐PAY FOR THEATRE PRODUCTIONS: INDIVIDUAL SPECIFIC WILLINGNESS‐TO‐PAY ESTIMATES FOR THEATRES,SHOWS AND THEIR ATTRIBUTES

This paper investigates people's preferences for live theatre, and heterogeneity in willingness‐to‐pay (WTP). A stated preference discrete choice model estimates utility and WTP for different attributes of theatre productions. Previous studies assumed fixed coefficients across all theatre‐goers. This study allows coefficients of attributes to vary across individuals in the population, providing information on the heterogeneity of tastes. Theatre‐goers' choices are used to estimate individual‐based parameters for a person's tastes in theatre productions. The analysis reveals the heterogeneity of tastes for different types of plays and ticket price; and the significance of ‘reviews’ by critics and ‘word of mouth’ opinions as important variables determining choice.     

Trust, Responsibility and the Interpretation of Contingent Valuation Results

Responses to contingent valuation questionnaires are contingent on respondent perceptions of trust and responsibility regarding aspects of the scenario presented to them. These issues can influence CV responses in several ways, with the net effect on WTP estimates depending on the relative prevalence of the different opposing effects in a given application. Whether such effects are to be considered biases, to be removed where possible, depends on the notion of validity one adopts. Whilst issues of trust and responsibility may pose little threat to predictive notions of validity, they are more problematic from a surplus validity, cost-benefit, perspective. Further discussion of the pros and cons of different validity notions for contingent valuation is required.