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DEALING WITH UNCERTAINTY ABOUT RISK IN RISK MANAGEMENT 52 original typesetting files. Page breaks are true to the original; line lengths, word breaks, heading styles, and other typesetting-specific formatting, however, cannot be About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the retained, and some typographic errors may have been accidentally inserted. Please use the print version of this publication as the authoritative version for attribution. Do Standard Setters Compensate for Conservative Risk Analysis? Regulatory decision makers may consider the details of the evidence supporting a risk estimate and compensate for perceived biases in analysis. If this is the case and appropriate adjustments are made, then standards will be the same no matter what risk-assessment assumptions are made. In this case, conservative analysis would not lead to either more stringent or less stringent standards than would mean, or best, estimates of risk. It is likely that conservatively estimated risks are discounted in some cases but not in others, and it is unlikely that such adjustments can be made appropriately and consistently. In the previous discussion of resource constraints, it was assumed that conservative estimates lead to stringent criteria. But it is apparent that conservatism in risk management need not be achieved through conservative risk assessment assumptions. For example, more stringent criteria for allowable risk, and less conservative assumptions for estimating risk, would yield current levels of protection. If greater use were made of this flexibility to vary risk criteria in response to conservatism in risk assessment, an attractive approach would be to select risk-assessment assumptions based on their discriminatory power. Relative risk estimates based on overly conservative assumptions may not distinguish important differences between risk. For example, an increase in benign liver tumors and a corresponding decrease in leukemias and mammary-gland fibroadenomas have been observed in response to test chemicals in the Fischer 344 rat (Haseman, 1983). Under present assessment methods, a carcinogen that increases benign tumors at one site but reduces malignant tumors at other sites might have the same assessed risk as one that increases the overall burden of malignant tumors. CONSERVATISM IN RISK ASSESSMENT: COMMENTS Even if efforts to be less conservative in risk assessment are accepted, there will be cases where no method for choosing between alternative assumptions is available. The best that risk analysis can provide when this happens is a collection of estimates based on a range of plausible models. Granger Morgan and his colleagues (1984) have taken this approach to describe the estimated health effects from sulfur air pollution. If less conservative assumptions were adopted for carcinogens, understanding the human-health implications of alternative animal bioassays would take on added importance. There would be apparent value in conducting a wide variety of animal tests with known human carcinogens as a means