Table A5. PROMIS applied cognition - general concerns item set: Final IRT item parameters and DIF statistics for the age groups, with the age 21 to 49 group as the reference.
| Item name | Group | a | b1 | b2 | b3 | b4 | aDIF* | bDIF* |
|---|---|---|---|---|---|---|---|---|
| I have had trouble forming thoughts | Age 21-49 | 4.98 (0.15) | -0.23 (0.02) | 0.34 (0.01) | 0.88 (0.02) | 1.31 (0.03) | NS, Anchor item | |
| Age 50-64 | ||||||||
| Age 65-84 | ||||||||
| My thinking has been slow | Age 21-49 | 5.66 (0.18) | -0.35 (0.02) | 0.22 (0.01) | 0.79 (0.02) | 1.21 (0.03) | NS, Anchor item | |
| Age 50-64 | ||||||||
| Age 65-84 | ||||||||
| My thinking has been foggy | Age 21-49 | 6.29 (0.20) | -0.22 0.02) | 0.33 (0.01) | 0.89 (0.02) | 1.31 (0.03) | NS, Anchor item | |
| Age 50-64 | ||||||||
| Age 65-84 | ||||||||
| I have had trouble concentrating | Age 21-49 | 6.46 (0.21) | -0.34 (0.02) | 0.23 (0.01) | 0.82 (0.02) | 1.22 (0.03) | DIF not significant | |
| Age 50-64 | ||||||||
| Age 65-84 | ||||||||
| I have had to work really hard to pay attention or I would make a mistake | Age 21-49 | 6.70 (0.35) | -0.18 (0.02) | 0.34 (0.02) | 0.82 (0.03) | 1.35 (0.04) | ||
| Age 50-64 | 6.57 (0.30) | -0.24 0.02) | 0.30 (0.02) | 0.82 (0.02) | 1.24 (0.03) | < 0.1 (0.893) | 10.9 (0.028) | |
| Age 65-84 | 6.24 (0.28) | -0.30 (0.02) | 0.32 (0.02) | 0.88 (0.03) | 1.26 (0.04) | 0.5 (0.471) | 19.5 (0.001) | |
| It has seemed like my brain was not working as well as usual | Age 21-49 | 7.12 (3.9) | -0.26 (0.03) | 0.19 (0.02) | 0.75 (0.02) | 1.20 (0.04) | ||
| Age 50-64 | 6.98 (0.32) | -0.29 (0.02) | 0.23 (0.02) | 0.72 (0.02) | 1.12 (0.03) | <0.1 (0.971) | 12.7 (0.013) | |
| Age 65-84 | 6.67 (0.30) | -0.32 (0.02) | 0.23 (0.02) | 0.75 (0.02) | 1.15 (0.04) | 0.04 (0.522) | 12.8 (0.012) | |
| I have had to work harder than usual to keep track of what I was doing | Age 21-49 | 7.34 (0.40) | -0.20 (0.02) | 0.26 (0.02) | 0.72 (0.02) | 1.17 (0.03) | ||
| Age 50-64 | 8.15 (0.42) | -0.25 (0.02) | 0.26 (0.02) | 0.74 (0.02) | 1.08 (0.03) | 3.1 (0.077) | 11.9 (0.018) | |
| Age 65-84 | 6.38 (0.28) | -0.30 (0.02) | 0.26 (0.02) | 0.77 (0.03) | 1.17 (0.04) | 2.7 (0.099) | 8.2 (0.084) | |
| I have had trouble shifting back and forth between different activities that require thinking | Age 21-49 | 6.23 (0.32) | -0.15 (0.02) | 0.35 (0.02) | 0.83 (0.03) | 1.25 (0.04) | ||
| Age 50-64 | 7.60 (0.37) | -0.22 (0.02) | 0.31 (0.02) | 0.77 (0.02) | 1.12 (0.03) | 10.4 (0.001) | 16.4 (0.003) | |
| Age 65-84 | 6.56 (0.30) | -0.28 (0.02) | 0.30 (0.02) | 0.81 (0.03) | 1.18 (0.04) | 1.2 (0.269) | 18.7 (0.001) | |
*
Statistical test for differences in parameters is Wald test using 1 df for the test of differences in the a parameters for the comparison groups and 2 df for the test of differences in the b parameters. “NS, Anchor item” refers to a non-significant DIF finding for the item during the initial iterative anchor item selection process. The “non-significant” designation refers to the second stage DIF detection procedure using the anchor items and testing the remaining items. The “non-significant” designation indicates that the item was not found to have DIF in the second stage of DIF detection.