Effects of Attribute Scales on Process and Performance in Multiattribute Choice

Abstract The type of scale used to represent the attributes of decision alternatives has received little attention in previous research, despite the pervasive presence of this issue in decision making. In two process tracing experiments we investigated how the type of scale used affects choices and choice processes. We hypothesized that scales affect the ease of accomplishing various component processes in choice. Experiment 1 used scales that differed in two ways: (1) whether all attributes were on the same scale (i.e., commonality) and (2) whether the scales were in units that were meaningful in the problem domain (i.e., context-relevance). We also manipulated economic incentives to favor speed over accuracy or the converse. Participants made more accurate decisions with common, context-independent scales but faster decisions with context-relevant scales. In addition, choice processes mediated the effects of scaling on both speed and accuracy. Experiment 2 replicated the results of Experiment 1 with decision contexts that differed in familiarity. Both experiments demonstrate that the scales used to present attributes can influence both the speed and accuracy of decision making, despite the presence of explicit economic incentives. Designers of choice studies and information displays are therefore advised to exercise care in choosing attribute scales.