INFLUENCE ALLOCATION METHODS IN GROUP DECISION-SUPPORT SYSTEMS

Influence allocation processes are voting and opinion aggregating meth ods that allow members to distribute some or all of their decision mak ing influence to others in the group in order to exploit not only the group's knowledge of the alternatives, but its knowledge of itself. On ly with the common use of group decision support systems (GDSS) has th eir use become practical. In this paper we reconsider SPAN, an influen ce allocation process introduced by MacKinnon (1966a). Experimental co mparison shows SPAN to be significantly better at selecting a correct option from a set of options than two common voting methods. An altern ative influence allocation process that we call RCON (Rational Consens us), is based on a weighting method proposed by DeGroot (1974) and has been explicated as a normative standard for combining opinion by Lehr er and Wagner (1981). The judgmental inputs to SPAN would appear to be logically related to those for RCON. Submitting the SPAN inputs from the experiment, transformed in this logical way, to the RCON process r esults in somewhat better performance than with SPAN. However, evidenc e indicated that the two methods are conceptually and psychologically sufficiently different that an experimental comparison is needed betwe en them.