Tiered chemical testing: A value of information approach
by Fumie Yokota, George Gray, James K. Hammitt, and Kimberly M. Thompson, Risk
In December 2000 the EPA initiated the Voluntary Children's Chemical Evaluation
Program (VCCEP) by asking manufacturers to voluntarily sponsor toxicological
testing in a tiered process for 23 chemicals selected for the pilot phase. The
tiered nature of the VCCEP pilot program creates the need for clearly defined
criteria for determining when information is sufficient to assess the potential
risks to children. This raises questions about how to determination the “adequacy”
of the existing information and assess the need to undertake efforts to reduce
uncertainty (through further testing). This paper applies a value of information
analysis approach to determine adequacy by modeling how toxicological and exposure
data collected through the VCCEP may be used to inform risk management decisions.
The analysis demonstrates the importance of information about the exposure level
and control costs in making decisions regarding further toxicological testing.
This paper accounts for the cost of delaying control action and identifies the
optimal testing strategy for a constrained decision maker who, absent applicable
human data, cannot regulate without bioassay data on a specific chemical. It
also quantifies the differences in optimal testing strategy for three decision
criteria: maximizing societal net benefits, ensuring maximum exposure control
while net benefits are positive (i.e., benefits outweigh costs), and controlling
to the maximum extent technologically feasible while the lifetime risk of cancer
exceeds a specific level of risk, and shows the large differences that exist
in net benefits between the three criteria for the range of exposure levels
where the optimal actions differ.
This study builds on reviews of the value of information literature, discussed
Yokota F, Thompson KM. Value of information literature analysis (VOILA): A
review of applications in health risk management. Medical Decision Making
Yokota F, Thompson KM. Value of information (VOI) analysis in environmental
health risk management (EHRM). Risk Analysis 2004;24(3):635-650.
From 2002-6 Professor Thompson served as a member of the Core Panel charged with reviewing VCCEP