Feasibility, validity and reliability of the ASCOT-Proxy and ASCOT-Carer among unpaid carers of people living with dementia in England

Table 6 Item statistics including difficulty (in logits), infit and outfit mean square and point-measure correlations for the ASCOT-Proxy-person

	ASCOT-Proxy-person					ASCOT-Proxy-person – collapsed categories^b
Scale domain (item)	Item difficulty	SE	INFIT MNSQ^a	OUTFIT MNSQ^a	Point-measure correlation	Item difficulty	SE	INFIT MNSQ^a	OUTFIT MNSQ^a	Point-measure correlation
Food and drink	-1.38	0.10	1.06	1.28	0.42	-1.38	0.20	0.98	1.06	0.27
Accommodation cleanliness and comfort	-1.53	0.12	0.94	0.95	0.43	-1.61	0.12	0.95	0.91	0.45
Personal cleanliness and comfort	-1.48	0.11	0.88	0.81	0.49	-1.56	0.11	0.92	0.94	0.48
Personal safety	-0.33	0.08	1.12	1.12	0.48	-0.36	0.09	1.09	1.09	0.51
Social participation and involvement	1.18	0.07	1.12	1.25	0.59	1.23	0.07	1.10	1.23	0.63
Control over daily life	1.37	0.07	0.81	0.78	0.72	1.41	0.13	0.82	0.75	0.59
Occupation	1.52	0.07	0.71	0.72	0.75	1.60	0.08	0.76	0.77	0.75
Dignity	0.64	0.08	1.29	1.33	0.45	0.66	0.08	1.29	1.33	0.49
ASCOT-Proxy-person (mean)	0.00	0.10	0.99	1.00		0.00	0.11	0.99	1.01

Abbreviations: Infit MNSQ Information-weighted mean square, Outfit MNSQ Outlier-sensitive mean square
^aValues in the range of .5 to 1.5 indicate a good fit
^bBased on the category response curves we collapsed two domains (items): the lowest two (high-level of unmet needs, some needs) and highest two categories (no needs, ideal state) were combined for food and drink and for control over daily life.

ISSN: 1477-7525