The Diversity Index is a scale of 0 to 100 that represents the likelyhood that two persons, chosen at random from the same area, belong to different race or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.
| County | Diversity Index | |
|---|---|---|
| 1. | Grant County | 27.9 |
| 2. | Ellis County | 29.9 |
| 3. | Alfalfa County | 33.4 |
| 4. | Roger Mills County | 34.0 |
| 5. | Lincoln County | 35.1 |
| 6. | Dewey County | 37.5 |
| 7. | Major County | 37.6 |
| 8. | Noble County | 37.8 |
| 9. | Grady County | 38.3 |
| 10. | Woods County | 38.3 |
| 11. | Washita County | 41.6 |
| 12. | McClain County | 42.2 |
| 13. | Pawnee County | 42.3 |
| 14. | Stephens County | 42.6 |
| 15. | Payne County | 43.1 |
| 16. | Logan County | 44.0 |
| 17. | Creek County | 44.7 |
| 18. | Jefferson County | 46.9 |
| 19. | Woodward County | 47.1 |
| 20. | Cotton County | 47.2 |
