Exploring a method to reduce inconsistency in the group Analytic Hierarchy Process using the Delphi method and Nudge theory

This paper reports a new method based on a Delphi process to nudge responses of participants toward consistency in an Analytic Hierarchy Process (AHP) study. We hypothesized that data collected during an early round of an AHP study could establish ranges of answers for later rounds that would improve consistency of responses. In our design, the Delphi method provided an effective framework for feedback of the bounds calculated between rounds. Using Delphi within the AHP to nudge answers of experts toward answers that promote consistency was the focus of our method. We propose an application using four mini scenarios depicting alternate futures for the management of genetic modification technologies. We found that in most instances our nudges improved the consistency of responses in sequential Delphi rounds; however, in some instances, the Delphi suggestions of bounds were not followed by a sufficient number of participants and a small number of inconsistencies remained. The value of this work may be in its warning to other researchers who attempt to achieve consistency by nudging responses in a paired comparison AHP study, to be quite explicit in instructions about remaining within the given bounds and perhaps creating incentives for respondents to do so.