Table 2.
Items of phase III and phase IV including difficulties, subdomains, item parameters, and fit indices
| Item | Difficulty rating | RF aspects | Slope | Location | Bias | Item fit p-value | Infit | Outfit |
|---|---|---|---|---|---|---|---|---|
| Item 1: Have you been limited in completing your household tasks? | Moderate | Work/activities | 2.731 | −0.784 | 0.02 | 0.651 | 0.95 | 0.73 |
| Item 2: Have you been limited in doing light housework (e.g. dusting or making the bed)? | Difficult | Work/activities | 3.093 | −1.059 | 0.01 | 0.836 | 0.94 | 0.60 |
| Item 3: Have you been limited in doing physically demanding recreational activities (e.g., swimming or cycling)? | Easy | Hobby/leisure | 1.907 | −0.259 | 0.03 | 0.331 | 0.95 | 0.79 |
| Item 4: Have you needed assistance in doing your work or daily activities? | Moderate | Work/activities | 2.736 | −1.019 | 0.01 | 0.857 | 0.93 | 0.68 |
| Item 5: Have you been limited in doing light recreational activities (e.g., watching TV, playing cards, or reading)?a | Difficult | Hobby/leisure | 1.986 | −1.346 | 0.00 | 0.084 | 1.03 | 0.66 |
| Item 6: Have you been limited in doing minor household repairs and maintenance (e.g., changing a light bulb or hanging up a picture)? | Moderate | Work/activities | 2.169 | −1.062 | 0.01 | 0.401 | 0.96 | 0.68 |
| Item 7: Have you been limited in taking care of personal or household financial affairs (e.g. paying bills)?ab | Difficult | Work/activities | 1.659 | −1.313 | 0.01 | 0.744 | 0.99 | 0.93 |
| Item 8: Were you limited in doing either your work or other daily activities?bc | Easy | Work/activities | 3.578 | −0.867 | 0.01 | 0.821 | 0.91 | 0.62 |
| Item 9: Have you been limited in doing heavy housework (e.g., washing floors or vacuuming)?b | Easy | Work/activities | 3.746 | −0.470 | 0.02 | 0.098 | 0.90 | 0.59 |
| Item 10: Were you limited in pursuing your hobbies or other leisure time activities?bc | Easy | Hobby/leisure | 2.144 | −0.666 | 0.02 | 0.211 | 0.96 | 0.78 |
| Item 11: Have you been limited in doing your work around the house? | Moderate | Work/activities | Excluded in phase IV | |||||
| Item 12: Have you been limited in doing the necessary shopping (e.g., for groceries or clothes)? | Moderate | Work/activities | Excluded in phase IV | |||||
afour response categories collapsed to two
bsignificant DIF (item 7: age – higher RF >60 years,item 8: work – higher RF when retired; partner – higher RF if no partner,item 9: country – higher RF in UK + Austria, item 10: gender – higher RF in women,)
cQLQ-C30 item