Table 2.

The scale of pairwise comparison.

Intensity of importance	Definition
1	Equal importance
3	Moderate importance of the first element over the second element in the pair
5	The strong or essential importance of the first element over the second element in the pair
7	Very strong importance of the first element over the second element in the pair
9	The extreme importance of the first element over the second element in the pair
2,4,6,8	An intermediate value between two adjacent judgments
Reciprocals of the above non-zero numbers	The inverse of the importance

Source: Saaty [44]