Environmental Risk Assessment System for Phosphogypsum Tailing Dams

Table 1

Scale of relative importance used in the pairwise comparison of AHP.

Linguistic variable	Scale of relative importance (crisp number)	Trapezoidal fuzzy number
Equally important	1	(1,1,1,1)
Weakly important	3	(2,5/2,7/2,4)
Essentially important	5	(4,9/2,11/2,6)
Very strongly important	7	(6,13/2,15/2,8)
Absolutely important	9	(8,17/2,9,9)
	𝑥=2,4,6,8 are intermediate scale	(𝑥−1,𝑥−1/2,𝑥+1/2,𝑥+1)