Scale

Definition

1

Two factors are compared, if the two factors are of equal importance

3

Two factors are compared, if one factor is slightly important than another

5

Two factors are compared, if one factor is obviously important than another

7

Two factors are compared, if one factor is significantly important than another

9

Two factors are compared, one factor is extremely important than another

2, 4, 6, 8

The median of the above two adjacent judgments

reciprocal

The ratio of the importance of factor $i$ to factor $j$ is $a_{ij}$

then the importance of factor $j$ to factor $i$ is $a_{ji}=1/a_{ij}$