Table 3.
Base rates of low scores on five NIHTB-CB fluid measures overall and by ability level in the normative sample
| Low scores | Age norms | Age norms by education level | Age norms by crystallized composite | Demographic norms | Demographic norms by crystallized composite | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 12 | 12 | 13–15 | 16+ | <90 | 90–99 | 100–109 | 110 + | <43 | 43–49 | 50–57 | 58+ | |||
| N | 843 | 81 | 222 | 201 | 332 | 201 | 201 | 213 | 228 | 793 | 78 | 204 | 229 | 194 |
| ≤25th percentile | ||||||||||||||
| 5 | 3.0 | 3.7 | 4.1 | 2.5 | 2.4 | 8.5 | 3.0 | 0.9 | 0.0 | 2.4 | 6.6 | 2.9 | 0.9 | 0.0 |
| 4+ | 8.8 | 17.3 | 9.5 | 8.0 | 6.9 | 21.4 | 10.9 | 3.8 | 0.4 | 7.7 | 16.3 | 12.3 | 3.1 | 1.0 |
| 3+ | 18.0 | 30.9 | 21.6 | 16.4 | 13.9 | 40.3 | 22.4 | 8.5 | 3.5 | 15.0 | 33.1 | 19.1 | 8.7 | 2.6 |
| 2+ | 35.1 | 53.1 | 40.1 | 32.3 | 28.9 | 61.2 | 42.8 | 26.8 | 13.2 | 32.8 | 60.8 | 37.3 | 24.9 | 13.4 |
| 1+ | 62.8 | 82.7 | 67.1 | 62.7 | 55.4 | 85.6 | 68.7 | 53.5 | 46.1 | 62.2 | 82.5 | 66.2 | 59.8 | 43.3 |
| None | 37.2 | 17.3 | 32.9 | 37.3 | 44.6 | 14.4 | 31.3 | 46.5 | 53.9 | 37.8 | 17.5 | 33.8 | 40.2 | 56.7 |
| ≤16th percentile | ||||||||||||||
| 5 | 0.7 | 2.5 | 0.5 | 1.0 | 0.3 | 3.0 | 0.0 | 0.0 | 0.0 | 0.9 | 3.6 | 0.5 | 0.0 | 0.0 |
| 4+ | 3.4 | 7.4 | 3.6 | 3.0 | 2.7 | 11.9 | 1.5 | 0.5 | 0.4 | 4.2 | 10.8 | 4.9 | 1.3 | 1.0 |
| 3+ | 9.5 | 16.0 | 9.5 | 8.5 | 8.7 | 22.4 | 10.9 | 4.2 | 1.8 | 9.8 | 22.9 | 12.7 | 5.2 | 1.0 |
| 2+ | 19.8 | 25.9 | 23.4 | 17.9 | 17.2 | 37.3 | 26.9 | 13.1 | 4.4 | 20.7 | 41.0 | 23.5 | 14.0 | 8.2 |
| 1+ | 42.7 | 56.8 | 49.5 | 38.8 | 37.3 | 67.7 | 49.3 | 34.7 | 22.4 | 45.9 | 74.7 | 48.0 | 39.7 | 26.3 |
| None | 57.3 | 43.2 | 50.5 | 61.2 | 62.7 | 32.3 | 50.7 | 65.3 | 77.6 | 54.1 | 25.3 | 52.0 | 60.3 | 73.7 |
| ≤9th percentile | ||||||||||||||
| 5 | 0.2 | 2.5 | 0.0 | 0.0 | 0.0 | 1.0 | 0.0 | 0.0 | 0.0 | 0.3 | 0.6 | 0.5 | 0.0 | 0.0 |
| 4+ | 1.2 | 4.9 | 0.9 | 0.5 | 0.9 | 4.5 | 0.5 | 0.0 | 0.0 | 1.4 | 6.0 | 1.0 | 0.4 | 0.0 |
| 3+ | 4.2 | 11.1 | 4.1 | 4.0 | 2.7 | 12.9 | 3.5 | 0.5 | 0.4 | 2.4 | 11.4 | 3.9 | 1.3 | 1.0 |
| 2+ | 11.2 | 19.8 | 12.6 | 11.9 | 7.5 | 26.4 | 13.9 | 4.7 | 1.3 | 8.1 | 27.7 | 14.7 | 6.1 | 3.1 |
| 1+ | 28.2 | 38.3 | 32.4 | 27.4 | 23.8 | 48.8 | 32.8 | 22.1 | 11.8 | 31.9 | 57.2 | 33.8 | 25.8 | 15.5 |
| None | 71.8 | 61.7 | 67.6 | 72.6 | 76.2 | 51.2 | 67.2 | 77.9 | 88.2 | 68.1 | 42.8 | 66.2 | 74.2 | 84.5 |
| ≤5th percentile | ||||||||||||||
| 5 | 0.1 | 1.2 | 0.0 | 0.0 | 0.0 | 0.5 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| 4+ | 0.4 | 2.5 | 0.5 | 0.0 | 0.0 | 1.5 | 0.0 | 0.0 | 0.0 | 0.4 | 1.8 | 0.0 | 0.0 | 0.0 |
| 3+ | 1.7 | 4.9 | 1.4 | 1.5 | 1.2 | 6.0 | 1.0 | 0.0 | 0.0 | 1.8 | 6.0 | 1.5 | 0.4 | 0.0 |
| 2+ | 5.3 | 12.3 | 5.0 | 4.5 | 4.2 | 15.4 | 6.0 | 0.5 | 0.4 | 4.7 | 14.5 | 4.4 | 0.9 | 1.0 |
| 1+ | 16.6 | 25.9 | 17.1 | 16.4 | 14.2 | 31.8 | 17.9 | 12.7 | 5.3 | 16.8 | 33.7 | 18.6 | 10.9 | 7.2 |
| None | 83.4 | 74.1 | 82.9 | 83.6 | 85.8 | 68.2 | 82.1 | 86.9 | 94.7 | 83.2 | 66.3 | 81.4 | 89.1 | 92.8 |
Note: The five tests are: Picture Sequence Memory, List Sorting Working Memory, Pattern Comparison Processing Speed, Flanker Inhibitory Control and Attention, and Dimensional Change Card Sort. Standard scores represent age-only adjustments. T-scores represent scores adjusted by age, sex, education level, and race/ethnicity.