| Definition of Importance | Scale |
| Factors have equal rank | 1 |
| One factor has weak rank over the other | 3 |
| One factor has strong rank over the other | 5 |
| One factor has demonstrated importance over the other | 7 |
| One factor has absolute rank over the other | 9 |
| Intermediate values used when factor importance lies between the odd numbers | 2, 4, 6, 8 |