Table 2.

Item Characteristics Based on a Rating Scale Model (FJS-CAT hip version)

# Item Content	MNSQ		Item Difficulty	Category Thresholds
	Infit	Outfit		1–2	2–3	3–4	4–5
01 in bed at night	1.36	1.24	0.33	− 0.68	0.03	0.24	1.74
02 sitting > 1 h	1.02	0.95	0.24	− 0.77	− 0.06	0.15	1.65
03 walking > 15 min	1.06	0.95	− 0.08	− 1.09	− 0.38	− 0.17	1.33
04 taking a bath/shower	1.11	1.04	1.07	0.06	0.77	0.98	2.48
05 travelling in a car	1.07	0.98	0.69	− 0.32	0.39	0.60	2.10
06 climbing stairs	0.88	0.76	− 0.31	− 1.32	− 0.61	− 0.40	1.10
07 walking on uneven ground	0.78	0.75	− 0.21	− 1.22	− 0.51	− 0.30	1.20
08 getting up from a low sitting position	0.98	1.02	− 0.08	− 1.09	− 0.38	− 0.17	1.33
09 standing for longer	1.04	1.23	− 0.18	− 1.19	− 0.48	− 0.27	1.23
10 housework or gardening	0.86	0.95	− 0.29	− 1.30	− 0.59	− 0.38	1.12
11 taking a walk/hiking	0.87	0.93	− 0.71	− 1.72	− 1.01	− 0.80	0.70
12 favorite sport	1.31	1.46	− 0.49	− 1.50	− 0.79	− 0.58	0.92

Final 12-item model: RMSEA 0.11.