Table 2.
Item Response Theory Parameter Estimates
| a | b1 | b2 | b3 | |
|---|---|---|---|---|
| Independence1 | 5.45 | 1.24 | 1.46 | – |
| Work | 3.58 | 0.02 | 0.58 | – |
| Social & Leisure Activities | 3.10 | 0.20 | 0.67 | 1.35 |
| Family & Friendships | 1.19 | 0.85 | 1.28 | 2.56 |
| Return to Normal Life | 1.46 | -0.61 | – | – |
a, discrimination parameter (i.e., strength of the relationship between the item and the latent disability dimension); b, difficulty parameter (i.e., disability/ability level assessed by each variable, for each step from between levels of the variable).
1
Independence combined Independence in the Home and Independence Outside the home into a 4-level ordinal item because of high correlation between these domains.