On consideration of the effectiveness of group decision making (GDM) in practical complex
decision problems, we introduce GDM into three-way decisions with decision-theoretic
rough sets (DTRSs) and propose GDM-based three-way decisions. GDM-based three-way
decisions extend the range of applications of three-way decisions with DTRSs and provide
a novel interpretation of the determination of loss functions. Based on DTRSs, we firstly
focus on analyzing the determination for the loss functions under the GDM environment.
With the aid of the principle of justifiable granularity, we adopt the important and majority
suggestions of experts to measure each loss function, which supports a coherent way of
designing information granules in presence of numerics. In this case, the loss functions are
determined in the form of interval-valued information granule. By using the interval comparison
method, we further deduce the three-way decisions and design a corresponding
decision procedure of GDM-based three-way decisions. Then, an example of strategy supply
selection is given to elaborate the GDM-based three-way decisions. Finally, we validate
the performance of our proposed method by experimental analysis.