Fig. 8. Weight of Evidence approach used in PATH (Marmorek and Peters 1998c). This process used sensitivity analysis to identify key uncertainties, systematically organized the evidence for and against alternative hypotheses for these uncertainties, elicited independent judgments from the SRP (Scientific Review Panel) on the relative probabilities of alternative hypotheses, and examined the consequences of these probability judgments in the decision analysis. Although management experiments were recognized as a much more rigorous approach to assigning probabilities to alternative hypotheses, such experiments may take decades. The Weight of Evidence process provides decision makers with a method of making a decision now, given current uncertainties, and clearly documents the rationale for this decision. See Appendix 4 for more details.