Table 1 Saaty’s fundamental comparison scale (1–9).

1

Equal importance/preference/likelihood

Two elements contribute equally to the goal/parent element

3

Weak dominance

Experience or judgment slightly favors one element over another

5

Strong dominance

Experience or judgment strongly favors one element over another

7

Demonstrated (very strong) dominance

Experience or judgment strongly very strongly favors one element over another (an element’s dominance is demonstrated in practice)

9

Absolute dominance

The evidence favoring an element over another is affirmed to the highest possible order

2, 4, 6, 8

Intermediate values

Further subdivision or compromise is needed

Reciprocals of the above

If activity i has one of the above nonzero numbers assigned to it when compared with activity j, then j has reciprocal value when compared with i

i.e., If x is 5 times y, then y = x/5

Rationals

Rations arising from the scale

If consistency were to be forced by obtaining n numerical values to span the matrix