Policy makers increasingly demand predictive information that can help guide political decision-making on controversial environmental issues that include global climate change, radioactive waste disposal, and mitigation of natural hazards such as hurricanes and earthquakes. As a result of this demand, major financial and intellectual resources in the earth sciences are now focused on the development of models and techniques for predicting the future behavior of natural and human-induced environmental phenomena Environmental problems and controversies are becoming more pervasive and severe. At the same time, research budgets are becoming tighter. Thus, the importance of effective prioritization and allocation of research funds and activities is increasing, as is the need for timely and effective political decision making. Whereas accurate, relevant predictions may help decision makers respond to some environmental problems, the misapplication or misuse of prediction research can undermine policy goals, waste scarce financial and intellectual resources, and erode the overall credibility of the scientific enterprise. For example, political response to given issue may be deferred in anticipation of the availability of accurate predictive data, even when the success of such a response does not depend on predictive knowledge. Neither policy makers nor scientists possess information necessary for understanding if, how, and when research focusing on prediction can be productively applied to policy making. This project begins a process of systematic analysis that can provide such information. Two workshops will be convened to bring scientists, policy makers, and policy analysts together to develop, present, and integrate case histories in predictive earth science research (past and ongoing). Workshops will focus on the delineation of principles and criteria that can help policy makers judge the potential value of scientific prediction as applied to different types of political and social problems related to the environment. Such principles and criteria may be necessary for the design of science and environmental policies that are fiscally responsible, scientifically efficient, and socially constructive. Towards this end, a significant component of this project will be the dissemination of workshop findings to the relevant scientific and policy-making communities through publications and presentations.