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Valuing Drinking Water Risk Reductions Using the Contingent Valuation Method: A Methodological Study of Risks from THM and Giardia (1986)

Paper Number: EE-0012

Document Date: 05/01/1986

Author(s):  Mitchell, Robert Cameron, Carson, Richard T

Subject Area(s):

Economic Analysis, Drinking Water, Trihalomethanes. THM, giardia, Contingent Valuation Survey

Keywords:  Economic Analysis, Drinking Water, Trihalomethanes, THM, giardia, Contingent Valuation Survey, Risk Ladder


This study develops contingent valuation methods for measuring the benefits of mortality and morbidity drinking water risk reductions. The major effort was devoted to developing and testing a survey instrument to measure the value of low-level risk reductions in community water systems from trihalomethanes (THMs). The study's first phase involved a program of qualitative work, including in-depth interviews and focus groups, conducted in southern Illinois, and area which suffers from excess THMs in drinking water supplies. The report provides in its appendices full documentation of the outcomes of this phase of study. 

On the basis of this effort a draft instrument was prepared which featured a risk ladder and other devices aimed at communicating THM risks in in-person interviews. This instrument was administered to a sample of 230 people in Herrin, IL. Chapters 4 and 5 present the finding which include various estimates of the value of a statistical life which are implied by these data. 

Chapter 6 presents the results of a preliminary effort to develop a contingent valuation instrument suitable for measuring the benefits of a Giardia prevention program in San Francisco. The approach described features a phone survey which simulates a referendum vote on whether San Francisco should install the equipment necessary to guarantee protection against the chance of an outbreak of giardiasis.

This paper is part of the  Environmental Economics Research Inventory.

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