Stability and agreement criteria for the termination of Delphi studies

This paper addresses the question of the methodology of testing for stability between successive Delphi rounds and the necessity of doing so prior to the analysis of the level or type of consensus. Following a discussion of a hierarchical set of a criteria for determining the termination of such studies, the paper reviews some of the more common treatments of the subject in the literature. It is finally proposed that a χ² test be used to test the stability of responses between rounds. The method is demonstrated by a numerical example.