Threshold-Enhanced PROMETHEE Group Decision Support under Uncertainties

Table 1

Aggregation levels in MCDM by a group decision.

Aggregation level	Comparison of the classifications		Example	Note
	Dias and Clímaco [18]	Shih [20]
Input level	Transfer the inputs of group members into the group’s input by an operator	External aggregation with preoperation	(1) Aggregation of individual judgments for AHP (Forman and Peniwati [21]); (2) Weighted sum of subjective ratings on some criteria by experts for TOPSIS (Parkan and Wu [22])	Aggregation at this level can be considered as teamwork instead of group decision.
Process level	Not available	Internal aggregation	(1) Aggregation of individual priorities for AHP (Forman and Peniwati [21]); (2) Establishment of group separation measure for TOPSIS (Shih et al. [19]) and considering differentiated decision power in the group (Shih [23]); (3) Weighting individual net flows to be the global evaluation for PROMETHEE (Macharis et al. [8])	This level of aggregation is rather diverse, depending on the procedures of MCDM techniques.
Output level	Transfer the results of group members into the group’s result by an operator	External aggregation via postoperation	(1) Aggregation of individual ranks from TOPSIS into a group rank by the Borda function (Shih et al. [24]); (2) Accumulation of the ranks of multijudges from PROMETHEE through social welfare functions (Colson [25])	Aggregation at this level operates by social choice functions for the group decision.