Table 1.
Descriptive Statistics for Each Sample with Verbal Reasoning
| Variable | HRS | UAS | CogUSA | CFAS | WLSG | WLSS | PSID |
|---|---|---|---|---|---|---|---|
| Age (years) | 67.40 (10.70) | 47.62 (15.49) | 64.54 (10.59) | 75.91 (6.48) | 64.31 (.68) | 63.91 (6.92) | 50.05 (14.16) |
| Age range | 18–104 | 17–98 | 38–94 | 67–99 | 63–67 | 40–87 | 30–97 |
| Gender (female) | 60% | 57% | 56% | 52% | 54% | 54% | 56% |
| Education (years) | 12.99 (2.94) | 11.06 (2.26) | 14.26 (2.32) | 11.88 (2.79) | 13.74 (2.33) | 13.52 (2.40) | 14.07 (2.22) |
| Race (white) | 76% | 82% | 89% | 100% | 100% | 100% | 66% |
| Race (African American/Black) | 17% | 8% | 6% | -- | -- | -- | 30% |
| Race (other/ unknown) | 7% | 10% | 5% | -- | -- | -- | 4% |
| Verbal Reasoning | 503.49 (29.35)a | 50.46 (8.73)b | 511.26 (26.76)a/ 54.96 (9.66)c | 6.65 (1.48)d | 6.64 (2.36)d | 6.70 (2.35)d | 3.88 (1.37)e |
| N | 13,398 | 5,800 | 1,212 | 2,092 | 5,924 | 3,120 | 7,631 |
Note. Numbers are means (standard deviations) or percentages. HRS=Health and Retirement Study. UAS=Understanding America Study. CogUSA=Cognition and Aging in the USA. CFAS= Cognitive Function and Ageing Study in Wales. WLSG=Wisconsin Longitudinal Study Graduate sample. WLSS= Wisconsin Longitudinal Study Sibling sample. PSID= Panel Study of Income Dynamics.
a
W-score based on IRT-parameters developed in HRS.
b
IRT score based on difficulty of the items.
c
Expressed as a T-score.
d
Sum of points across items.
e
Sum of correct responses.