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. | Harris County | 88.3 |
| 2. | Dallas County | 88.2 |
| 3. | Fort Bend County | 85.8 |
| 4. | Bexar County | 84.3 |
| 5. | Moore County | 84.3 |
| 6. | Waller County | 84.0 |
| 7. | Brazoria County | 83.3 |
| 8. | Tarrant County | 83.2 |
| 9. | Potter County | 83.2 |
| 10. | Titus County | 82.9 |
| 11. | Ector County | 82.5 |
| 12. | Bee County | 82.4 |
| 13. | Caldwell County | 82.3 |
| 14. | Matagorda County | 82.3 |
| 15. | Wharton County | 81.8 |
| 16. | Karnes County | 81.8 |
| 17. | Bastrop County | 81.4 |
| 18. | Winkler County | 81.4 |
| 19. | Midland County | 81.4 |
| 20. | Bell County | 81.3 |