Ratio and Difference Estimation in Multi-Criteria Decision Analysis
Abstract Since decisions are invariably made within a given context, we model relative preferences as ratios of increments or decrements in an interval on the axis of desirability. Next, we sort the ratio magnitudes into a small number of categories, represented by numerical values on a geometric scale. We explain why the Analytic Hierarchy Process (AHP), typically based on a pairwise-comparison method, is concerned with category judgement of ratio magnitudes, whereas the Simple Multi-Attribute Rating Technique (SMART) essentially uses the orders of magnitude of these ratios. This provides a common basis for the analysis of the methods in question and for a cross-validation of their results. The present paper summarizes the basic assumptions and the relationship between the two methods.