Willingness to accept equals willingness to pay for labor market estimates of the value of a statistical life

Our research clarifies the conceptual linkages among willingness to pay for additional safety, willingness to accept less safety, and the value of a statistical life (VSL). We present econometric estimates using panel data to analyze the VSL levels associated with job changes that may affect the worker’s exposure to fatal injury risks. Our baseline VSL estimates are $7.7 million and $8.3 million (Y$2001). There is no statistically significant divergence between willingness-to-accept VSL estimates associated with wage increases for greater risks and willingness-to-pay VSL estimates as reflected in wage changes for decreases in risk. Our focal result contrasts with the literature documenting a considerable asymmetry in tradeoff rates for increases and decreases in risk. An important implication for policy is that it is reasonable to use labor market estimates of VSL as a measure of the willingness to pay for additional safety.     

Valuing Mortality-Risk Reduction: Using Visual Aids to Improve the Validity of Contingent Valuation

We investigate the validity of contingent valuation (CV) estimates of the value per statistical life (VSL). We test for sensitivity of estimated willingness to pay (WTP) to the magnitude of mortality-risk reduction and for the theoretically predicted proportionality of WTP to risk reduction using alternative visual aids to communicate risk. We find that WTP is sensitive to the magnitude of risk reduction for independent subsamples of respondents presented with each of three alternative visual aids, but not for the subsample presented with no visual aid. Estimated WTP is consistent with proportionality to risk reduction for the subsamples presented with a logarithmic scale or an array of 25,000 dots, but not for the subsample receiving a linear scale. These results suggest that CV can provide valid estimates of WTP for mortality-risk reduction if appropriate methods are used to communicate the risk change to respondents.     

Admissible utility functions for health, longevity, and wealth: integrating monetary and life-year measures

The value of reducing health and mortality risks is often measured using value per statistical life (VSL) or one of several life-year measures (e.g., life years, quality-adjusted life years, disability-adjusted life years). I derive the utility function that is admissible when preferences for health and longevity, conditional on wealth, are consistent with any life-year measure (LYM) and examine the implications for marginal willingness to pay (WTP) for increases in health, longevity, and current-period survival probability. I conclude that marginal WTP for any LYM is decreasing and that VSL is increasing in the LYM. These results imply that cost-effectiveness analysis using a fixed monetary value per LYM is not consistent with economic welfare theory and that the benefit of a health improvement cannot be calculated by multiplying the change in a LYM by a constant.     

Risk Perceptions and Value of a Statistical Life for Air Pollution and Traffic Accidents: Evidence from Bangkok,Thailand

This paper presents results of two contingent valuation surveys conducted in Bangkok measuring individuals’ willingness to pay (WTP) to reduce mortality risk arising from two risk contexts: air pollution traffic accidents Results from the risk perception survey disclose that respondents view the two risks differently. WTP to reduce air pollution risk is influenced by degrees of dread, severity, controllability and personal exposure, while WTP to reduce traffic accident risk is influenced by perceived immediate occurrence. Nevertheless, the value of a statistical life (VSL) for both air pollution and traffic accidents are comparable (US$0.74 to $1.32 million and US$0.87 to $1.48 million, respectively). This indicates that the risk perception factor alone has little impact on the VSL, a finding similar to previous studies using program choice indifferences.JEL Classification: I18, D61, J17, J28     

The value of mortality risk reductions in Delhi,India

We interviewed commuters in Delhi, India, to estimate their willingness to pay (WTP) to reduce their risk of dying in road traffic accidents in three scenarios that mirror the circumstances under which traffic fatalities occur in Delhi. The WTP responses are internally valid: WTP increases with the size of the risk reduction, income, and exposure to road traffic risks, as measured by length of commute and whether the respondent drives a motorcycle. As a result, the value of a statistical life (VSL) varies across groups of beneficiaries. For the most highly-exposed individuals the VSL is about 150,000 Purchasing Power Parity (PPP) dollars.

Policy relevant heterogeneity in the value of statistical life: New evidence from panel data quantile regressions

We examine differences in the value of statistical life (VSL) across potential wage levels in panel data using quantile regressions with intercept heterogeneity. Latent heterogeneity is econometrically important and affects the estimated VSL. Our findings indicate that a reasonable average cost per expected life saved cut-off for health and safety regulations is 7 million to7 million to 8 million per life saved, but the VSL varies considerably across the labor force. Our results reconcile the previous discrepancies between hedonic VSL estimates and the values implied by theories linked to the coefficient of relative risk aversion. Because the VSL varies elastically with income, regulatory agencies should regularly update the VSL used in benefit assessments, increasing the VSL proportionally with changes in income over time.     

The heterogeneity of the value of statistical life: Introduction and overview

The refinement in worker fatality risk data used in hedonic wage studies and evidence from new stated preference studies have facilitated the exploration of the heterogeneity of the value of statistical life (VSL). Although the median VSL estimate for workers is $7–$7–8 million, the VSL varies considerably within the worker population. New estimates of the income elasticity of VSL are 1.0 or above, which are consistent with theoretical models linking VSL to the coefficient of relative risk aversion. The specific relationship between VSL and risk aversion is, however, more complex than previously understood. Age differences in VSL are substantial, with young children being accorded especially high VSL amounts. The public’s willingness to pay to reduce risks is reduced if those being protected are perceived as being blameworthy due to their responsibility for contributing to the risk.     

Anchoring biases in international estimates of the value of a statistical life

U.S. labor market estimates of the value of a statistical life (VSL) were the first revealed preference estimates of the VSL in the literature and continue to constitute the majority of such market estimates. The VSL estimates in U.S. studies consequently may have established a reference point for the estimates that researchers analyzing data from other countries are willing to report and that journals are willing to publish. This article presents the first comparison of the publication selection biases in U.S. and international estimates using a sample of 68 VSL studies with over 1000 VSL estimates throughout the world. Publication selection biases vary across the VSL distribution and are greater for the larger VSL estimates. The estimates of publication selection biases distinguish between U.S. and international studies as well as between government and non-government data sources. Empirical estimates that correct for the impact of these biases reduce the VSL estimates, particularly for studies based on international data. This pattern of publication bias effects is consistent with international studies relying on U.S. estimates as an anchor for the levels of reasonable estimates. U.S. estimates based on the Census of Fatal Occupational Injuries constitute the only major set of VSL studies for which there is no evidence of statistically significant publication selection effects. Adjusting a baseline bias-adjusted U.S. VSL estimate of $9.6 million using estimates of the income elasticity of the VSL may be a sounder approach for generating international estimates of the VSL than relying on direct estimates from international studies.     

Effects of Disease Type and Latency on the Value of Mortality Risk

We evaluate the effects of disease type and latency on willingness to pay (WTP) to reduce environmental risks of chronic, degenerative disease. Using contingent-valuation data collected from approximately 1,200 respondents in Taiwan, we find that WTP declines with latency between exposure to environmental contaminants and manifestation of any resulting disease, at a 1.5 percent annual rate for a 20 year latency period. WTP to reduce the risk of cancer is estimated to be about one-third larger than WTP to reduce risk of a similar chronic, degenerative disease. The value of risk reduction also depends on the affected organ, environmental pathway, or payment mechanism: estimated WTP to reduce the risk of lung disease due to industrial air pollution is twice as large as WTP to reduce the risk of liver disease due to contaminated drinking water.     

Scope insensitivity in health risk reduction studies: A comparison of choice experiments and the contingent valuation method for valuing safer food

Scope insensitivity and embedding are fundamental concerns in contingent valuation studies for health risk reductions. Recently, choice experiments have increasingly been used to obtain contingent willingness to pay (WTP) estimates. We juxtapose the WTP estimates of a choice experiment (CE) to those of the contingent valuation method (CVM) for different health risk reductions and compare them in the extent of scope insensitivity and embedding. WTP using CVM is scope sensitive for single health risks, but embedding is observed for multiple disease risks. In contrast, WTP based on the CE is highly scope sensitive and convex in risk reduction levels.

Background Risks and the Value of a Statistical Life

We examine the effects of background mortality and financial risks on an individual's willingness to pay to reduce his mortality risk (the value of statistical life or VSL). Under reasonable assumptions about risk aversion and prudence with respect to wealth in the event of survival and with respect to bequests in the event of death, background mortality and financial risks decrease VSL. The effects of large mortality or financial risks on VSL can be substantial, but the effects of small background risks are negligible. These results suggest that the commonplace failure to account for background risk in evaluating VSL is unlikely to produce substantial bias in most applications.     

Willingness to Pay for Health Protection: Inadequate Sensitivity to Probability?

Efficient investments in health protection require valid estimates of the public's willingness to forgo consumption for diminished probabilities of death, injury, and disease. Stated valuations of risk reduction are not valid measures of economic preference if the valuations are insensitive to probability variation. This article reviews the existing literature on CV studies of reductions in health risk and finds that most studies are poorly designed to assess the sensitivity of stated valuations to changes in risk magnitude. Replication of a recent study published in this journal by Johannesson et al. (1997) demonstrates how serious the problem of insensitivity can be, even for a study that reports plausible results. New empirical results are presented from telephone surveys designed to provide internal and external tests of how WTP responds to size of risk reduction. The effect of variations in instrument design on estimated sensitivity to magnitude is examined. Overall, estimated WTP for risk reduction is inadequately sensitive to the difference in probability, that is, the magnitude of the difference in WTP for different reductions in risk is typically smaller than suggested by standard economic theory. Additional research to improve methods for communicating changes in risk is needed, and future studies of stated WTP to reduce risk should include rigorous validity checks.     

Individual and Household Values of Mortality Reductions with Intrahousehold Bargaining

I derive alternative measures of maximum willingness to pay (WTP) and value of statistical life (VSL) for selfish members of two-person households who bargain efficiently over consumption of individual and household goods. There is then no systematic bias in letting one member conduct the valuation on behalf of the household. Public-good VSL may exceed private-good VSL when each member attaches (selfish) preferences to survival of the spouse, and to any income from a surviving spouse in period 2. When period 2 is a retirement period and household members’ incomes are fixed, interview surveys tend to overvalue VSL due to ignored negative effects of own survival on private of public pension budgets.JEL Classification: I12, G22, J17     

A Choice Experiment Approach to the Valuation of Mortality

This paper presents an integrated framework for evaluating the reduction of several types of mortality risk using a Choice Experiment (CE) approach, a type of stated preference technique. Using this approach, we can distinguish the marginal willingness to pay (MWTP) for the amount of risk reduction from the MWTP for the opportunity of risk reduction and therefore calculate the “Quantity-based” Value of a Statistical Life. The risks in our survey include mortality risks due to accident, cancer, and heart disease. The Quantity-based VSL is calculated to be 350 million JPY (in 2002 Japanese Yen, about 2.9 million US dollars). Furthermore, we analyzed the influence of subjective risk perception and population characteristics of the respondents on their MWTP. Estimated results suggest that it is unnecessary to adjust the VSL according to the differences in the type of risk if the VSL is calculated using an adequate approach. However, adjustments for the timing of risk reduction and population characteristics are found to be significant for the execution of benefit transfer.JEL Classification: I18, D81, J17     

Age,autos, and the value of a statistical life

The value of a statistical life (VSL) is used to assign a dollar value to the benefits of health and safety regulations. Many of those regulations disproportionately benefit older people, but most estimates of the VSL come from hedonic wage regressions with few older workers and no retirees. Using automobile purchase decisions, I estimate a VSL for individuals from the age of 18 up to the age of 85. Combining information on vehicle holdings and use, household attributes, used vehicle prices, crash test results, and yearly fatal accidents for each make, model, and vintage automobile, I calculate a separate willingness to pay for reduced mortality for different age groups. I find a significant inverted-U shape to the age-VSL function that ranges from $1.5 to $19.2 million (in 2009 dollars). The shape and magnitude of the vehicle-based age-VSL relationship corroborate labor market estimates and extend the age range of revealed preference evidence on the relationship between age and the VSL.     

Precautionary behavior and willingness to pay for a mortality risk reduction: Searching for the expected relationship

This paper examines within-sample correlation between six different precautionary behaviors and stated willingness to pay for a mortality risk reduction. The paper also shows estimates of the value of a statistical life based on seat belt and bicycle helmet use as well as based on the stated willingness to pay for a risk reduction in traffic mortality. Contrary to the theoretical expectations, no correlation is found between precautionary behavior and stated willingness to pay. One major explanation is that females and the elderly take more precaution, but state a lower WTP for a risk reduction. The estimates of VSL from the different approaches are $11.0 million, $5.0 million and $2.8 million from stated WTP, bicycle helmet use and seat belt use, respectively.

Valuing fatal risks to children and adults: Effects of disease,latency, and risk aversion

We examine heterogeneity of willingness to pay (WTP) to reduce risks of fatal disease and trauma to adults and children. Using a stated-preference survey fielded to a large, nationally representative internet panel, we find that WTP to reduce fatal-disease risks (caused by consuming pesticide residues on foods) are similar for several types of cancer and non-cancer diseases and similar to WTP to reduce motor-vehicle crashes. WTP to reduce risk to one’s child is uniformly larger than to reduce risk to another adult or to oneself. Estimated values per statistical life are $6–10 million for adults and $6–10 million for adults and 12–15 million for children.     

Does the WTA/WTP ratio diminish as the severity of a health complaint is reduced? Testing for smoothness of the underlying utility of wealth function

The aim of the study reported in this paper is to test the hypothesis that individual utility of wealth functions may violate the assumption of smoothness that underpins the standard analysis of the Value of Statistical Life (VSL) and safety. In order to do so we examine the way in which the Willingness to Accept/Willingness to Pay (WTA/WTP) ratio varies as the severity of a health complaint is reduced. We find that as the severity of the health effect is reduced, the WTA/WTP ratio converges across the sample and tends to a level that does not significantly exceed unity. While we acknowledge that this does not constitute conclusive evidence of smoothness, it does suggest that the case in favour of the assumption that individual utility of wealth functions tend to display a kink at the current level of wealth is less than wholly persuasive.     

Imprecise preferences and the WTP-WTA disparity

This article reports the results of a study designed to elicit willingness to pay (WTP) and willingness to accept (WTA) values for changes in the risk of nonfatal road injuries. We examine the possibility that individuals' preferences over combinations of wealth, risk, and safety are imprecise, and that this imprecision might result in the observed disparity between WTP and WTA measures of value. The results confirm that individuals' preferences for safety are significantly imprecise, but that this alone is insufficient to explain more than part of the disparity. Indeed, respondents' estimates of the minimum that they would be prepared to accept for a risk increase frequently exceed the maximum that they would be prepared to pay for an equivalent risk reduction.     

Age, Health and the Willingness to Pay for Mortality Risk Reductions: A Contingent Valuation Survey of Ontario Residents

We present the results of a contingent valuation survey eliciting willingness to pay (WTP) for mortality risk reductions. The survey was self-administered using a computer by 930 persons in Hamilton Ontario aged 40 to 75. Visual and audio aides were used to enhance risk comprehension. Mean WTP figures for a contemporaneous risk reduction imply a value of a statistical life of approximately C$l.2 to C$3.8 million (1999 C$). Mean WTP is constant with age up to 70 years, and is about 30 percent lower for persons aged 70 and older. WTP is unaffected by physical health status, but is affected by mental health.