Survey sponsor effects on the willingness to pay for mortality risk reductions
This research shows that when the monetary value people place on their health is measured by surveys, the type of institution sponsoring those surveys has an effect on that value. This occurs especially when the question is asked by government agencies: in such surveys, respondents place a significantly lower value on their health – up to 25 per cent lower. In theory, the identity of those posing the question should not influence a person’s own ‘true’ valuation of their health, yet it is a picture observed even when state-of-the-art survey methods are used.
The study was carried out in the Mexico Valley metropolitan area (MVMA), which includes Mexico City, where air pollution levels frequently breach the Mexican and international standards considered acceptable for human health. Mexico has increasingly been using cost–benefit analysis, including the monetisation of health benefits from reductions in air pollution, to inform decisions on environmental policy.
These research results show that caution must be exercised when environmental and health policy decisions are based on cost–benefit comparisons as benefits may vary significantly by type of survey sponsor. This conclusion is generalisable to other countries.
Key points for decision-makers
- This research uses the value of a statistical life (VSL) as a proxy for the monetary value people place on their health.
- It finds that the type of institution sponsoring surveys asking people to place a value on their health influences their answer, with a significantly lower valuation generally being made when governments are the survey conductors.
- Value of a statistical life measures are typically used by governments to, for example, decide the level of stringency at which to set legislation to reduce air pollution, or whether to offer a certain type of medication in a public health system. This is done by comparing the costs and benefits of different options and placing a value on the benefits using the monetary value of health.
- As the valuation a person makes of their health varies depending on who is asking them, the decision of whether or not to go ahead with a policy is also influenced by the identity of the survey conductor. This is a concern because the types of decisions that are made using such surveys directly affect people’s health.
- Governments should therefore be made aware of this survey sponsor effect and take it into account in analyses supporting public policy decisions.
- More research is needed into why the survey sponsor effect occurs, even when using state-of-the-art surveys, and if these surveys can be improved.
- The research was carried out in Mexico but the results offer insights for other countries.
ISSN 2515-5717 (Online)