Asking for Individual or Household Willingness to Pay for Environmental Goods?

The aggregate welfare measure for a change in the provision of a public good derived from a contingent valuation (CV) survey will be higher if the same elicited mean willingness to pay (WTP) is added up over individuals rather than households. A trivial fact, however, once respondents are part of multi-person households, it becomes almost impossible to elicit an “uncontaminated” WTP measure that with some degree of confidence can be aggregated over one or the other response unit. The literature is mostly silent about which response unit to use in WTP questions, and in some CV studies it is even unclear which type has actually been applied. We test for differences between individual and household WTP in a novel, web-administered, split-sample CV survey asking WTP for preserving biodiversity in old-growth forests in Norway. Two samples are asked both types of questions, but in reverse order, followed by a question with an item battery trying to reveal why WTP may differ. We find in a test between samples that the WTP respondents state on behalf of their households is not significantly different from their individual WTP. However, within the same sample, household WTP is significantly higher than individual WTP; in particular if respondents are asked to state individual before household WTP. Our results suggest that using individual WTP as the response unit may overestimate aggregate WTP. Thus, the choice of response format needs to be explicitly and carefully addressed in CV questionnaire design and further research in order to avoid the risk of unprofitable projects passing the benefit-cost test.

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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.     

Use of Contingent Valuation to Elicit Willingness-to-Pay for the Benefits of Developmental Health Risk Reductions

We report the results of several contingent valuation (CV) surveys to elicit willingness-to-pay values from the general public for risk reductions associated with decreases in exposure to a chemical, PCBs, in the environment. We also develop Quality Adjusted Life Years (QALYs) from the survey using both standard gamble and time-tradeoff elicitation methods to explore the relationship between QALYs and willingness-to-pay (WTP), and to develop QALY weights for subtle developmental effects. The results of the CV surveys are designed for incorporation into a case study of an integrated risk model to monetize the benefits of predicted risk reductions. Respondents showed a nearly proportional, positive relationship between decreasing the risk of a 6-point reduction in IQ (a standard measure of “intelligence”) and WTP, but showed a negative relationship between risk reduction and WTP for reading comprehension as an outcome. The range of mortality risks that respondents would accept on behalf of their (hypothetical) 10-year-old child is 2 in 10,000 to 9 in 1,000 per IQ point, and WTP per IQ point is $466 ($380, $520). QALY weights elicited via time tradeoff (reduction in life expectancy) were significantly different from QALY weights elicited via a standard gamble (p = 0.001). Respondents who answered questions about ecological endpoints first were willing to pay a small additional amount when asked about human health effects, but those respondents who answered questions about human health endpoints first were not willing to pay any additional amount when subsequently asked about ecological effects. This paper has not been submitted elsewhere in identical or similar form, nor will it be during the first three months after its submission to the Publisher.     

Extracurricular participation and risky behaviours during high school

Extracurriculars may reduce risky behaviours (smoking, alcohol, marijuana use) through human and health capital accumulation, crowding out and positive peer influences but may also increase them through peer pressure. Using data from the National Education Longitudinal Study, we estimate the contemporaneous and longer term effects of extracurricular participation on 10th and 12th grade risky behaviours. Joint estimation of the participation and risky behaviour decisions, which corrects for selection into extracurriculars, shows that extracurricular activities lead to substantial reductions in the likelihood of engagement in risky behaviours, particularly for smoking and marijuana, but these effects are not persistent in the longer run.     

Past and present outage costs – A follow-up study of households’ willingness to pay to avoid power outages

Households’ demand for electricity continues to increase. This trend per se should indicate increased disutility from power outages. Additionally, batteries and other back-up systems have been improved, and the frequency and duration of outages have been reduced in many countries. By comparing the results from two stated preference studies on Swedish households’ willingness to pay (WTP) to avoid power outages in 2004 and 2017, we investigate whether the WTP has changed. The WTP is assessed for power outages of 1- and 4 -h durations, and whether it is planned or unplanned. We find three main differences: (i) the proportion of households stating zero WTP to avoid power outages decreased significantly from 2004 to 2017, meaning that more households are willing to pay to avoid a power outage in 2017 than in 2004; (ii) the overall WTP was considerably higher in 2017 than in 2004, but (iii) the conditional WTP, that is, WTP for those that have a positive WTP for an outage, has decreased. These results have implications for how regulators incentivize and regulate electricity suppliers, because the results suggest that a reliable supply of electricity is of greater importance now than what the literature has suggested.     

Willingness-to-pay for urban ecosystem services provision under objective and subjective uncertainty

There is growing concern that failure to acknowledge the risk and uncertainty surrounding ecosystem services (ES) delivery could have adverse effects on support for ES policy intervention in the long run. However, acknowledging risk may reduce support for policy interventions in the short term. In this paper, we sought to determine whether willingness-to-pay (WTP) for urban forest ES in Southampton, UK is affected by objective and subjective uncertainty surrounding ES delivery. We conducted a discrete choice experiment with a split sample design: one with a scenario specifying risky ES outcomes and one where zero risk was implied. Respondents’ subjective certainty surrounding the provision of ES was determined before and after the choice questions. Despite respondents’ risk aversion, introducing an objective likelihood attribute did not reduce WTP compared to the scenario with implied certain ES outcomes. Furthermore, whilst WTP for the overall scheme was found to be adversely affected by the presence of risk around ES outcomes, subjective uncertainty seemed to reduce WTP more than objective probabilities. Our results therefore support the idea that both objective probabilities and subjective uncertainty should be explicitly incorporated in the design of stated preference studies for ES valuation.     

You should know better! Do health students have different risk attitudes to unplanned pregnancy and sexually transmitted diseases?

Because healthcare professionals are in the best position to assess, assist and educate those participating in risky sexual behaviour, understanding if (and how) their risk attitudes differ from the wider population is of vital importance. In this study, we explore university health students’ risk attitudes towards unplanned pregnancy and sexually transmitted diseases (STDs). We examine whether university students pursuing health-related degrees, who hypothetically should have more exposure to and understanding of the risks associated with unplanned pregnancy and STD, have more risk averse attitudes to sexual behaviour. We find that health students’ sexual attitudes are significantly more risk averse than those of their nonhealth peers in relation to STDs but not unplanned pregnancy. In line with previous research, age and no previous sexual history (virginity) appear to increase risk-averse attitudes to both unplanned pregnancy and STDs. Moreover, males and singles are more risk seeking in their sexual attitudes. These findings suggest that, because unplanned pregnancy and STDs are ongoing global issues, further research is warranted into the risk attitudes of those healthcare professionals most able to provide education and support for individuals participating in risky sexual behaviour.     

A Preface to the Economic Analysis of Disease Transmission

Infectious diseases are transmitted from person to person or from vectors such as mosquitos to people. The uninfected take precautions against these diseases and the infected try to mitigate their symptoms and to get cured. In doing so, people may weigh the costs of illness, prevention and therapy. They may also (altruistically) weigh the costs of people whom their own behavior puts at risk, for instance their sexual partners, or they may act entirely selfishly. Some of these behaviours may therefore lead to externalities and a corresponding rationale for government interventions. A recent literature uses economics to investigate the implications of rational choice by individuals about their response to infectious diseases. It analyzes decisions about prevention, vaccination, testing, therapies and government intervention. This paper reviews this literature with an emphasis on examples from the HIV/AIDS epidemic.     

Economic Development,Risky Sexual Behavior,and AIDS Epidemics—Theory and Evidence

In this paper, we present a simple theoretical model to investigate how economic development affects AIDS epidemics through its influence on individuals’ sexual behavior, building on the literature on economic growth with endogenous mortality concern. We employ provincial data from China on the incidence rate of AIDS between 2002 and 2008 to test the theoretical predictions. The findings are: (1) a rise in personal income/wealth induces more safe sexual activities and reduces the prevalence of AIDS; and (2) increases in public health expenditure do not have a significant positive impact on individuals’ preference of risky sexual activity over safe sexual activity.     

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 .     

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.     

Some issues in the application of closed-ended willingness to pay studies to valuing health goods: an application to antenatal care in Scotland

Limited resources coupled with unlimited demands means that decisions have to be made concerning the allocation of scarce health care resources. The economic instrument of willingness to pay (WTP) is one instrument that can be used to help this decision-making process. Recommendations from the environmental economics literature suggest that the closed end (CE) WTP approach should be used. This approach is just beginning to be used to value health goods. This paper addresses the sensitivity of the closed-ended WTP approach to three issues: the design of the bid vector; the upper and lower limits of integration; and the method of analysis. These are discussed with reference to a study looking at the value of alternative models of ante-natal care in Scotland. The results are discussed and conclusions made concerning the use of the CE WTP instrument for valuing health goods.     

The impact of the bird flu on public willingness to pay for the protection of migratory birds

In this paper, we present the results of a unique time series analysis of contingent values and models for migratory bird protection based on an identical contingent valuation (CV) survey carried out over a three year time period since the first bird flu outbreak in 2003. Although there exists no scientific evidence for a direct relationship, migratory birds are believed to play an important role in spreading the bird flu virus worldwide. The time series analysis allows us to test the temporal stability of stated preferences for migratory bird protection and at the same time examine indirectly the possible impact of increased media attention and public awareness levels regarding the bird flu. We test the impact of the bird flu on public willingness to pay (WTP) for migratory bird protection in the final 2005 survey whilst accounting for procedural variance introduced by sequencing and question ordering-effects, but we are unable to demonstrate a direct negative relationship. A novelty of the study presented here is that respondents in the CV surveys are given the opportunity to pay an annual money amount or a one-time-off lump-sum. Annual WTP values appear to be significantly higher than one-time-off WTP values, suggesting a negative implicit discount rate. Self-selection bias is an important reason for the observed differences. We find that respondents who agree to pay annually differ significantly from respondents who wish to pay a lump-sum in terms of their underlying preferences and motivations towards migratory bird protection.     

Willingness to pay for publicly-financed health care: how should we use the numbers?

This paper addresses the question of how willingness to pay (WTP) values in health care evaluation can be used by policy makers. The way in which WTP values are used depends on from whom values are elicited and whether the good concerned is privately-financed or publicly-financed through taxation. Thus, four possible uses of WTP values are identified. The focus is on the two uses which arise in the publiclyfinanced situation. ‘Conventional’ use of WTP values, where the decision as to whether or not to provide a service depends upon whether or not WTP values are greater than total cost, applies only in the privately-financed, and not publiclyfinanced situations. The situations with publicly-financed goods are more complex. The use of WTP values for publicly-financed goods is justified and illustrated.     

Parametric and Semi-Nonparametric Estimation of Willingness-to-Pay in the Dichotomous Choice Contingent Valuation Framework

Standard procedures for extractingwillingness-to-pay (WTP) from dichotomouschoice CV questionnaires rely heavily uponparametric assumptions regarding thedistribution and form of WTP in the sampledpopulation. However, theory provides littleguidance regarding which parametricspecification to use and the resulting WTPestimates can be sensitive to the selectionsmade. Here we compare and contrast severalparametric and semi-nonparametric estimatorsthat have been proposed in the literature,examining the sensitivity of the resulting WTPestimates to the underlying distribution ofpreferences and the estimation procedureemployed.     

Modeling self-censoring of polluter pays protest votes in stated preference research to support resource damage estimations in environmental liability

The identification and treatment of protest response in stated preference (SP) research such as contingent valuation is an underdeveloped area. Protest related to the polluter pays principle (PPP) is expected to pose an important hurdle to the application of SP research in environmental liability claims, for instance under the European Environmental Liability Directive. Our main objective is to test the effect of PPP induced protest votes on welfare measures for lost passive use value using different treatment procedures. We argue for a more reliable and defensible indicator of willingness to pay (WTP) in environmental liability litigation cases than current standard removal practices in cases where protest votes affect sample representativeness. Analyzing the impact of PPP-based protest response on WTP values with the help of a Full Information Maximum Likelihood sample selection model, a significant correlation is found between the decision to participate in the CV market and the WTP bids. Self-censoring biases average WTP and is correlated with factors such as respondent use of the resource and disposition towards its future protection. Simply removing protest response from the sample is indefensible and results in a biased estimation of WTP.     

The determinants of household recycling: social influence,public policies and environmental preferences

Our article aims at understanding the determinants of households’ selective waste-sorting behaviours, based on data from an original survey of 694 individuals in the French Provence–Alpes–Côte d’Azur region. The applied literature focuses mainly on countries with high recycling rates. We focus on a region with the lowest recycling rate in France, a country that recycles less than the European country average. We first apply polychoric principal components analysis to reduce the number of explanatory variables to a set of six factors. In a second step, we use a probit model to estimate the probability of waste sorting as a function of these factors. This model tests several hypotheses emerging from the recent literature on behavioural economics applied to households’ selective sorting. This literature pays particular attention to the social influence on recycling behaviour, which has been studied mostly by sociologists and psychologists. The results of our empirical analysis confirm some of the findings in the literature. However, they also highlight some unique features, such as social influences having a negative impact on recycling. This finding contrasts with most of the literature, which finds a positive relationship of social influence on pro-environmental behaviour.     

Proportionality of Willingness to Pay to Small Changes in Risk: The Impact of Attitudinal Factors in Scope Tests

Sensitivity (proportionality) of willingness to pay (WTP) to (small) risk changes is often used as a criterion to test for valid measures of economic preferences. In a contingent valuation (CV) study conducted in Austria, 1,005 respondents were asked their WTP for preventing an increase in the risk of being killed in an avalanche of 1/42,500 and 3/42,500 respectively. WTP for the higher variation in risk is significantly greater than WTP for the lower risk change. We find evidence that those respondents who have had personal experience of avalanches in recent years combine the information about future risk increase—as provided in the survey—with the observed number of fatal avalanche accidents in the past. Proportionality of WTP holds if such prior experience is taken into account and if attitudinal factors in scope tests are controlled for. This research was funded by alpS GmbH—Center for Natural Hazard Management, Innsbruck, Austria.     

Giving Stated Preference Respondents “Time to Think”: Results From Four Countries

Previous studies have found that contingent valuation (CV) respondents who are given overnight to reflect on a CV scenario have 30–40% lower average willingness-to-pay (WTP) than respondents who are interviewed in a single session. This “time to think” (TTT) effect could explain much of the gap between real and hypothetical WTP observed in experimental studies. Yet giving time to think is still rare in binary or multinomial discrete choice studies. We review the literature on increasing survey respondents’ opportunities to reflect on their answers and synthesize results from parallel TTT studies on private vaccine demand in four countries. Across all four countries, we find robust and consistent evidence from both raw data and multivariate models for a TTT effect: giving respondents overnight to think reduced the probability that a respondent said he or she would buy the hypothetical vaccines. Average WTP fell approximately 40%. Respondents with time to think were also more certain of their answers, and a majority said they used the opportunity to consult with their spouse or family. We conclude with a discussion of why researchers might be hesitant to adopt the TTT methodology.     

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.