Multicriteria analysis of aeromedical fleet expansion

摘要

We present an Expected Multiattribute Utility analysis of an aeromedical program's decision to add helicopters to its existing fleet. We approach the problem as one of helping the program's executive director to synthesize the relative value of the alternatives along technical dimensions so that he can present the alternatives to a decision making board that will weigh the technical merits against nontechnical dimensions, such as public perception, in deciding whether to expand the fleet. We develop criteria and simulation models to predict the joint probability distributions over these criteria for the different alternatives and use a combination of strength of preference and lottery-based questions in carefully planned utility assessments. To acknowledge difficulties in utility assessments, we perform a comprehensive sensitivity analysis of the utility information and note that our “best guess” results are fairly insensitive to the modeled variations. We propose the use of a “ratio of utility differences” to give a feel for the relative difference in the technical value between a given alternative and the status quo alternative, where the scale is the difference in value between another pair of alternatives easily perceived by the decision makers. This easy-to-use ratio implies that, although adding a helicopter to the program's fleet is optimal according to the technical dimensions, the additional “technical value” is small enough that the important nontechnical considerations could be expected to dominate the ultimate decision.