As described in the Uniformity Report, the utilities currently assign LoF values to risky events using a 1 to 7 scale. The scale defines event frequencies or rates” as demonstrated below. As referred to in Section 5, the utility “arrival scales are similar to Richter scales, which are based on of magnitude.” “order According to Joint Intervenors, this 1 to 7 scale is because the “nonlinear” underlying rates” or frequencies represent changes in a way that are “hazard similar to order of magnitude differences. They observe, this scale “Moreover, means that an event occurring every 35 years has the same LoF (2) as an event occurring every 90 years, an event occurring every 3 years has the same LoF (4) as an event occurring every 9 years, and so forth, even though the mathematical probabilities of these events are different.” In essence, 1 to “the 7 LoF values do not correspond to mathematical probabilities.” 1 2 3 4 5 6 7 Remote Rare Infrequent Occasional Frequent Regular Common Once every Once Once every Once every Once every 110 >10 times per 100+ years every 1030 years 310 years 13 years per year year 30100 years Joint Intervenors also point out that the utilities do not use a consistent set of for each attribute. it appears that the weights are set “weights” “Instead, independently of the attribute ranges by individuals who did not specify the attribute ranges. Therefore, there is no reason to believe that either risk reduction will be measured correctly using such attribute weights.” Also, the utilities use rather than values in their scales. (If a scale “discrete” “continuous”
As described in the Uniformity Report, the utilities currently assign LoF values to risky events using a 1 to 7 scale. The scale defines event frequencies or “arrival rates” as demonstrated below. As referred to in Section 5, the utility scales are similar to Richter scales, which are based on “order of magnitude.” According to Joint Intervenors, this 1 to 7 scale is “nonlinear” because the underlying “hazard rates” or frequencies represent changes in a way that are similar to order of magnitude differences. They observe, “Moreover, this scale means that an event occurring every 35 years has the same LoF (2) as an event occurring every 90 years, an event occurring every 3 years has the same LoF (4) as an event occurring every 9 years, and so forth, even though the mathematical probabilities of these events are different.” In essence, “the 1 to 7 LoF values do not correspond to mathematical probabilities.” 1 2 3 4 5 6 7 Remote Rare Infrequent Occasional Frequent Regular Common Once every 100+ years Once every 30100 years Once every 1030 years Once every 310 years Once every 13 years 110 per year >10 times per year Joint Intervenors also point out that the utilities do not use a consistent set of “weights” for each attribute. “Instead, it appears that the weights are set independently of the attribute ranges by individuals who did not specify the attribute ranges. Therefore, there is no reason to believe that either risk reduction will be measured correctly using such attribute weights.” Also, the utilities use “discrete” rather than “continuous” values in their scales. (If a scale
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