A Mixed Logit Approach to Study Preferences for Safety on Alpine Roads

This paper presents a mixed logit approach to the valuation of reductions in mortality risk on Alpine roads. In addition to common road accidents, users of these roads face risks from natural hazards such as avalanches and rockfalls. Moreover, the individual risk of road users varies with the frequency of their exposure. Drawing on choice experimental data of frequently exposed respondents from a mountainous region and less frequently exposed respondents from a city in Switzerland, we are able to estimate the value of statistical life (VSL). Furthermore, we explore how respondents differ in their individual willingness-to-pay depending on exposure and other individual characteristics. Our estimates of the VSL in the context of fatal accidents on Alpine roads are in the range of CHF 6.0–7.8 million (€3.9–5.1 million). We find the VSL to be dependent on socio-economic and perceptional factors but to be not significantly altered by the type of hazard. These findings imply that the VSL might be adjusted to account for heterogonous risk preferences of different societal groups, but there is no evidence of a ‘dread’ premium for natural hazards.     

Implementing QALYs in the Analysis of Air Pollution Regulations

In recent years, there has been growing interest in cost-effectiveness analysis for environmental regulations using quality-adjusted life years as the measure of effectiveness. This paper explores the implications of the QALY approach for measuring the impacts of air pollution regulations, with an example using the U.S. Environmental Protection Agency’s Heavy Duty Engine/Diesel Fuel regulations. The paper also examines the issues surrounding the potential use of QALY measures in cost-benefit analysis for air pollution regulations. Key findings are that, compared with a cost-benefit approach, the QALY framework gives more weight to reductions in incidence of chronic disease relative to reductions in premature mortality risk, especially when the mortality risk reductions occur in older populations. In addition, use of monetized QALYs in cost-benefit analysis is not recommended, due to fundamental differences in the theoretical grounding of the different measures. However, application of monetized QALYs based on age-specific willingness to pay (WTP) for mortality risk reductions gives very similar results to typical cost-benefit analysis for mortality risk reductions, as opposed to using values for QALYs based on non-age specific WTP. The paper concludes that in cases where mortality provide the majority of a regulation’s impacts, QALY based cost-effectiveness analysis and WTP based cost-benefit analysis may not differ in their conclusions. However, in cases where morbidity or non-health outcomes are significant, cost-effectiveness and cost-benefit analysis may result in different evaulations of the efficiency of the regulation.     

Context and the VSL: Evidence from a Stated Preference Study in Italy and the Czech Republic

We report on the results of a survey based on conjoint choice experiments that was specifically designed to investigate the effect of context on the Value of a Statistical Life (VSL), an important input into the calculation of the mortality benefits of environmental policies that reduce premature mortality. We define “context” broadly to include (1) the cause of death (respiratory illness, cancer, road traffic accident), (2) the beneficiary of the risk reduction (adult v. child), and (3) the mode of provision of the risk reduction (public program v. private good). The survey was conducted following similar protocols in Italy and the Czech Republic. When do not distinguish for the cause of death, child and adult VSL are not significantly different from one another in Italy, and the difference is weak in the Czech sample. When we distinguish for the cause of death, we find that child and adult VSLs are different at the 1% level for respiratory illnesses and road-traffic accidents, but do not differ for cancer risks. We find evidence of a “cancer premium” and a “public program premium.” In both countries, the marginal utility of income is about 20% lower among wealthier people, which makes the VSL about 20% higher among respondents with incomes above the sample average. The discount rate implicit in people’s choices is effectively zero. We conclude that there is heterogeneity in the VSL, and that such heterogeneity is primarily driven by risk characteristics mode of delivery of the risk reduction, and income, while other individual characteristics of the respondent (e.g., age and education) are less important. For the most part, our results are in agreement with environmental policy analyses that use the same VSL for children and adults, and that apply a cancer premium.     

Exploring heterogeneity in the value of a statistical life: Cause of death v. risk perceptions

Most current environmental policy analyses use Value of a Statistical Life (VSL) figures inferred from workplace safety and traffic accident contexts to compute the benefits of environmental programs that avoid premature deaths. There is considerable debate about the appropriateness of this practice, in part because the effect of cause of death may be partly confounded with latency, initial risks, and competing risks. Preference for reducing risks can be also affected by individual-assessed risk attributes that are rarely controlled in valuation studies. This paper explores reasons for differences in preferences for mortality risk reductions (if any), and establishes the magnitude of the effects of such risk attributes as compared to other sources of VSL heterogeneity. In our conjoint choice experiments, cause of death, the size of the risk reduction, and latency, the “price” of the risk reduction and the mode of delivery of the risk reduction are explicit attributes of the alternatives to be examined by the respondent. Our statistical models also control for actual and perceived exposure to risks, initial risks, risk attributes such as dread, and sensitivity to and controllability of specific risks. We find that there is significant heterogeneity in the valuation of mortality risks and thus in the VSL. The VSL increases with dread, exposure to risk, and the respondents' assessments of the baseline risks. It is higher when the risk reduction is delivered by a public program, and increases with the effectiveness rating assigned by the respondent to the mode of the risk reduction. Even when we control explicitly for all of these factors, the cause of death per se accounts for a large portion of the VSL. All else the same, the fact that the cause of the death is “cancer” results in a VSL that is about one million euro above the amount predicted by dread, exposure and other risk perception variables. The VSL in the road safety context is about one million euro less than what is predicted by dread, exposure, or beliefs compared to VSL for the respiratory risk context. The effect of cause of death is thus as large as the effect of other sources of VSL heterogeneity. Our respondents do not seem to discount future risks.     

Valuing Mortality Risk in Kuwait: Stated-Preference with a New Consistency Test

We report stated-preference estimates of the value per statistical life (VSL) for Kuwaiti citizens obtained using an innovative test to identify respondents whose survey responses are consistent with economic theory. The consistency test requires that an individual report strictly positive willingness to pay (WTP) for mortality-risk reduction and that his responses to binary-choice valuation questions for two risk reductions be consistent with the theoretical requirement that WTP is less than but close to proportional to the change in risk reduction. Our estimates of VSL, $18–32 million, are approximately two to four times larger than values accepted for the United States. These values may reflect cultural factors as well as the substantially larger disposable income of Kuwaiti citizens.     

Pricing Lives: International Guideposts for Safety

Government agencies throughout the world use the value of a statistical life (VSL) to monetise the mortality risk reduction benefits of government policies. The most reliable empirical estimates of the VSL using US labour market data are about US$10 million (year 2015 US dollars). Based on international estimates of the income elasticity of the VSL, one can transfer these values to other countries, leading to my VSL estimate for Australia of US$7.9 million, or A$10.0 million, which is over double the current Australia best‐practices value. Transferring US VSL estimates to other nations after accounting for income differences will boost global VSL estimates. Potential refinements of the VSL based on age and income are also feasible. The VSL could serve a pivotal role in promoting safety by valuing lives in litigation contexts, regulatory sanctions, and corporate risk analyses.     

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.     

The Effect of Risk Characteristics on the Willingness to Pay for Mortality Risk Reductions from Electric Power Generation

The objective of this study is to estimate willingness to pay (WTP) for the reduction of mortality risks caused by fossil fuel (natural gas, coal and oil) versus nuclear electric power generation systems and to examine the influence of risk characteristics involved with electric power generation on WTP. A choice experiment was conducted to achieve these objectives. The attributes for nuclear risks in the experiment included the probability of disasters and the expected losses if a disaster occurs. We find evidence of (i) a baseline effect (where WTP is sensitive to hypothetical versus actual baseline expected mortality); (ii) a ‘labeling effect,’ where, surprisingly, the term ‘nuclear’ has no effect on WTP, but the term ‘fossil-fueled power generation’ results in lower WTP; and (iii) disaster aversion, meaning that people focus on the conditional loss from a nuclear disaster, not the probability. We also find that the WTP for reducing deaths from a nuclear disaster is about 60 times the WTP for routine reducing fossil-fuel generation-related deaths.     

Do we really care about Biodiversity?

This paper addresses from an economic perspective the issue of global biodiversity conservation. It challenges the perception that the world really cares a great deal about biodiversity and is prepared to pay the full cost of maintaining this stock of natural capital. Despite the existence of a plethora of international agreements there still seems to be a global ‘deficit of care’ surrounding efforts to combat challenges such as those posed by global warming and biodiversity conservation. More light can be thrown on the degree of care by measuring both the actual expenditures and the stated willingness to pay for biodiversity conservation. However, actual expenditures are much lower than willingness to pay estimates recorded in the published literature. Using the criteria that the ‘right’ amount of conservation effort is one where the marginal economic benefits from conservation just equal the marginal costs of conservation, the paper explores the biodiversity conservation conundrum and concluded that, on the available evidence, the world does not care too much about this natural capital stock and bequests to future generations. An erratum to this article can be found at     

The Willingness to Accept Value of Statistical Life Relative to the Willingness to Pay Value: Evidence and Policy Implications

Large disparities between willingness to accept (WTA) and willingness to pay (WTP) based values of statistical life are commonly encountered in empirical studies. Standard economic theory suggests that if a public good is easily substitutable there should be no marked disparity between WTA and WTP values for the good, though the disparity increases with reduced substitutability. However, psychologists have shown that people often treat gains and losses asymmetrically and tend to require a substantially larger increase in wealth to compensate for a loss than the amount they would be willing to pay for an equivalent gain. Although most transport projects may aim to improve safety, situations arise when a relaxation of an existing regulation saves resources but increases the risk of death and injuries. A survey was recently carried out in New Zealand to determine people’s willingness to pay to reduce road risks and their willingness to accept compensation for an increase in risk. This paper reports the disparity observed between the two measures and considers some of the problems posed for policymakers.     

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.     

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.     

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 missing piece: Valuing averting behavior for children's ozone exposures

Individuals can reduce their exposure to air pollution by reducing the amount of time they spend outdoors. Reducing outdoor time is an example of an averting behavior that should be measured as part of willingness to pay (WTP) for improvements in air quality. In this paper, we estimate parents’ WTP to prevent restrictions on a child's outdoor time from a stated-preference (SP) conjoint survey. We combine this WTP measure with an estimate of reductions in time spent outdoors on high-ozone days from an activity-diary study to estimate this averting behavior component of WTP for reductions in ozone pollution.     

Willingness to pay for improving fatality risks and asthma symptoms: Values for children and adults of all ages

We examine effects of age on valuation of mortality and morbidity risks using a two-stage contingent valuation survey and a sample including parents of children aged 4–17 years and adults aged 18–92. The survey used a hypothetical improved asthma therapy to elicit (1) tradeoffs between asthma control and fatality risk, (2) willingness to pay (WTP) for reduced fatality risk, and (3) WTP for asthma control. The mean value of statistical life (VSL) at average age is $3.8M, but age affects VSL and nonlinearly. Estimated VSL is highest at age four ($14.1M), falls until age 30 ($3.7M), rises until age 66 ($6.7M), and then falls to $1.5M by age 92. Results from the wide age range considered may partly reconcile apparently conflicting results from previous studies focused on narrower age ranges. The value of asthma control is not as strongly related to age as VSL and ranges from $1700 to $4000 annually.     

Estimating Mortality and Economic Costs of Particulate Air Pollution in Developing Countries: The Case of Nigeria

The value of statistical life is an essential parameter used in ascribing monetary values to the mortality costs of air pollution in health risk analyses. However, this willingness to pay estimate is virtually non-existent for most developing countries. In the absence of local estimates, two major benefit transfer approaches lend themselves to the estimation of the value of statistical life: the value transfer method and the meta-regression analysis. Using Nigeria as a sample country, we find that the latter method is better tailored than the former for incorporating many characteristics that vary between study sites and policy sites into its benefit transfer application. It is therefore likely to provide more accurate value of statistical life predictions for very low-income countries. Employing the meta-regression method, we find Nigeria’s value of statistical life estimate to be $489,000. Combining this estimate with dose response functions from the epidemiological literature, it follows that if Nigeria had mitigated its 2006 particulate air pollution to the World Health Organisation standards, it could have avoided at least 58,000 premature deaths and recorded an avoided mortality related welfare loss of about $28 billion or 19 % of the nation’s GDP for that year.     

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.     

Compensating Wage Differentials with Unemployment: Evidence from China

We estimate the economic value of mortality risk in China using the compensating-wage-differential method. We find a positive and statistically significant correlation between wages and occupational fatality risk. The estimated effect is largest for unskilled workers. Unemployment reduces compensation for risk, which suggests that some of the assumptions under which compensating wage differentials can be interpreted as measures of workers’ preferences for risk and income are invalid when unemployment is high. Workers may be unwilling to quit high-risk jobs when alternative employment is difficult to obtain, violating the assumption of perfect mobility, or some workers (e.g., new migrants) may be poorly informed about between-job differences in risk, violating the assumption of perfect information. These factors suggest our estimates of the value per statistical life (VSL) in China, which range from approximately US$30,000 to US$100,000, may be biased downward. Alternative estimates adjust for heterogeneity of risk within industry by assuming that risk is concentrated among low-skill workers. These estimates, which are likely to be biased downward, range from US$7,000 to US$20,000.      

Model Uncertainty,Ambiguity and the Precautionary Principle: Implications for Biodiversity Management

We analyze ecosystem management under ‘unmeasurable’ Knightian uncertainty or ambiguity which, given the uncertainties characterizing ecosystems, might be a more appropriate framework relative to the classic risk case (measurable uncertainty). This approach is used as a formal way of modelling the precautionary principle in the context of least favorable priors and maxmin criteria. We provide biodiversity management rules which incorporate the precautionary principle. These rules take the form of either safety margins and minimum safety standards or optimal harvesting under precautionary approaches.