| SCALE | TRANSFORMATION GROUP | ALLOWABLE STATISTICS | EXAMPLES |
| Nominal | Identity | Mode(s) | Proper names; technical terms |
| Typological | Permutation | Mode(s) | Taxonomy of plants and animals; etiology of diseases |
| Ordinal | Isotonic | Median; range | Moh mineral hardness scale; IQ; Richter-Kanamori earthquake scale |
| Interval | Linear | Arithmetic mean; variance | densities;Celsius & Fahrenheit temperature scales |
| Ratio | Similarity | all statistics | weight, length, etc. |