Comparing Apples And Oranges: Combining Data On Value Judgments. Resha M. Putzrath, Step 5 Corporation, 1101 17th Street, NW, Suite 501, Washington, DC 20036
Value judgments are often measured in non-linear scales and expressed in terms other than probability or margins-of-safety. Yet when consideration is given to these components of risk management, such quantities must be combined and/or compared with more familiar measures of risk. One procedure that attempts to resolve this dilemma is to convert all values into a common metric. Some metrics, however, are themselves associated with values. For example, some people object to the use of dollars as the common metric because it assigns a price to a human life or to existence of a species, either of which they may view as inestimable. Even converting to more neutral systems of measuring diverse quantities, e.g., lives saved, assumes that the formula for interconversion is constant over the range to be evaluated. Often this is not the case. An alternative method that allows each attribute to remain in its own metric is proposed. Each aspect is measured in the most convenient metric, and value demarcations, de minimis to critical, are determined. Composites of the ranked values are then used for comparison and for selection of critical issues for further consideration.