Valuing a Reduction in The Risk of Asthma: A Large-Scale Multi-Country Stated Preference Approach

Asthma is a non-communicable and non-curable lung disease that affects one in ten children and four in a hundred adults worldwide and that is associated with an array of environmental contaminants and chemicals. Many of these hazards are subject to regulation, or may be considered for regulation, in order to reduce exposures and prevent human health risks. However, valuation estimates for a reduction in the risk and severity of asthma that can be used in cost-benefit analyses are few, particularly willingness-to-pay estimates. In particular, the available information on willingness-to-pay (WTP) to avoid asthma or reduce its severity is incomplete and does not provide estimates compatible with welfare economic theory. This paper is part of the series of large scale WTP studies resulting from the Surveys to elicit Willingness to pay to Avoid Chemicals related negative Health Effects (SWACHE) project that intends to improve the basis for doing cost benefit analyses of chemicals management options and environmental policies in general. The present paper offers values suitable for use in costbenefit analyses of the willingness to pay for reduced severity of asthma in adults and children and in reduced probability of getting asthma for these two population groups, all in the context of reducing chemical exposures, and covering populations in seven OECD countries: Canada, Czech Republic, France, Poland, Sweden, the United Kingdom and the United States. This paper applies two stated preference methods: the contingent valuation methods for eliciting willingness to pay (WTP) for reduced asthma severity and choice experiments for eliciting WTP for reduced probability of getting asthma of various severities. The context for such elicitations was a set of household products that contain fewer hazardous chemicals than what is currently available in supermarkets but are more expensive.

Asthma can be classified in five severity steps: mild, mild plus, moderate, moderate plus and severe depending on the intensity and frequency of symptoms, their impacts on the quality of life and the risk of hospitalisation and complications. The study finds that the WTP for reducing adult asthma severity by one step, e.g. from “moderate plus” to “moderate”, is USD2022 Purchasing Power Parity-adjusted 529 per year on average The parental WTP for reducing asthma severity in their children is on average 1.8 times higher than their WTP for themselves at USD2022 948 per year. WTP for a reduction in asthma severity varies between USD2022 PPP 430 per year for Canada and USD2022 PPP 770 per year for Sweden for adult asthma, and between USD2022 PPP 740 for the United Kingdom and USD2022 PPP 1 300 for the United States for childhood asthma. The mean Value of a Statistical Case (VSC) of adult asthma which would be applied to predictions of new cases of asthma avoided by a regulation equals USD2022 280 000 while the mean VSC of childhood asthma equals USD2022 430 000. Country-specific VSC of asthma vary between USD2022 PPP 200 000 for the United Kingdom and USD2022 PPP 370 000 for Poland in the case of adult asthma and vary between USD2022 PPP 350 800 for Canada and USD2022 PPP 610 000 for the United States in the case of childhood asthma.

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