Table 2. Results of Mokken scale analysis on the items of the BI-SS (n = 306).

		Self-perceived Difficulty Scale	Ability Scale
Item		Hi	Hi
1	Feeding	0.49	0.59
2	Grooming	0.55	0.61
3	Dressing	0.67	0.69
4	Bathing	0.64	0.71
5	Bowels	0.68	-
6	Bladder	0.62	-
7	Toilet use	0.71	0.82
8	Transfer	0.66	0.80
9	Mobility	0.63	0.76
10	Stairs	0.62	0.79
Scale H		0.63	0.75