 One key area of socially relevant interdisciplinary science is risk assessment, which involves both research on the effects of various substances or practices and the evaluation of those effects once identified. The idea is to gain an understanding of both positive effects and of negative effects and a method of evaluating these. This involves integrating the work of specialists in the kind of substance whose risks are under assessment (geneticists, chemists, physicists), biomedical specialists, epidemiologists, statisticians, and so on. In these cases, we are dealing not only with the problems of trust and authority among specialists from different disciplines, but also with the effects of introducing new technologies or new substances into the world. The risks studied are generally of harm to human health or to the environment. Interest in applying philosophical analysis to risk assessment originated in response to debates about the development and expansion of nuclear power-generating technologies. In addition, the application of cost-benefit analysis and attempts to understand decision-making under conditions of uncertainty became topics of interest as extensions of formal modeling techniques (Giere 1991). These discussions intersect with debates about the scope of rational decision theory and have expanded to include other technologies as well as applications of scientific research in agriculture and in the myriad forms of biological engineering. Essays on the relation between science and social values in risk research collected in the volume edited by Deborah Mayo and Rachelle Hollander (1991) attempt to steer a course between uncritical reliance on cost-benefit models and their absolute rejection. Coming from a slightly different angle, the precautionary principle represents an approach shifting the burden of proof in regulatory decisions from demonstration of harm to demonstration of safety of substances and practices. Carl Cranor (2004) explores versions of the principle and defends its use in certain decision contexts. Shrader-Frechette (2002) has advocated models of ethically weighted cost-benefit analysis and greater public involvement in risk assessment. In particular she (Shrader-Frechette 1994, 2002) has argued for including members of the public in deliberations about health effects of and reasonable exposure limits on environmental pollutants, especially radioactive materials. Philosophers of science have also worked to make visible the ways in which values play a role in the research assessing the effects of techno-scientifically produced substances and practices themselves, as distinct from the challenges of assigning values to identified risks and benefits.