A Novel Approach to Reducing Uncertainty

A variation on the conventional Delphi was used to assemble an informational summary of expert opinion regarding the risks involved with the application of sewage sludge to farmland. The aim was to reduce uncertainties surrounding the associated health and environmental risks so agreement among citizens, farmers, and regulators could be reached. An expert panel was assembled for one day to take part in a structured communication process modeled after the Delphi. A two-part questionnaire using Likert scaling and open questions was iterated among rotating subgroups to build consensus and define disagreement. Plenary discussions were held between iterations to foster peer review. There was consensus about the risks of heavy metals, pathogens, and nutrients; but clear disagreement about the risks of organic toxins. Existing state regulations were deemed inadequate only for lead and some organic toxins. Expert quantitative ratings were found to differ radically for two hypothetical contexts: academic and public. Statement of the Problem: Decision Under Uncertainty Rarely do decision makers feel they have enough information available to make a decision about which they can be confident. Among regulators, politicians, managers, and public officials, considerable effort is expended in reducing uncertainty surrounding decisions. Uncertainty reflects incomplete knowledge. Depending on the type of knowledge, different techniques have proved effective at resolving uncertainties. Uncertain knowledge about factual evidence (random error, statistical error) can be resolved by scientific methodology and the peer review process, whereas uncertain knowledge about values (social priorities or preferences) can be reduced by political discourse or democratic voting procedures. But the domains of these two procedures to reduce uncertainty are not inclusive to all kinds of knowledge. Uncertainties about predicting future events and uncertainties