An extension of TOPSIS, a novel trapezoidal intuitionistic fuzzy TOPSIS method for group decision making
is investigated. The preference values for an alternative on criteria and the weight values of criteria are given by experts
represented with trapezoidal intuitionistic fuzzy numbers and weights of decision makers are unknown. Distance measures,
expected values and weighted averaging operator for trapezoidal intuitionistic fuzzy numbers are used to induce the weight
values of criteria and decision makers. Then an algorithm is developed for ranking alternatives under the trapezoidal
intuitionistic fuzzy environment. Finally, the result of numerical example further illustrates the effectiveness of the proposed
extended TOPSIS method.