Development and validation of a new patient-reported outcome measure for patients with pressure ulcers: the PU-QOL instrument

Table 4 Summary of PU-QOL Rasch analysis, field test 2

Scale (No. of items)	Disordered thresholds	Item locations logits range	Fit statistics fit residuals outside +/−2.5	Items with Chi square probability significance ≥0.001	Person separation index	DIF age		DIF gender		DIF HC setting
Scale (No. of items)	Disordered thresholds	Item locations logits range	Fit statistics fit residuals outside +/−2.5	Items with Chi square probability significance ≥0.001	Person separation index	Uni	Non	Uni	Non	Uni	Non
Pain (8)	0	-1.11 − 1.03	0	0	0.72	0	0	0	0	0	0
Exudate (8)	1	-0.75 – 0.84	1	1	0.69	0	0	0	0	0	0
Odour (6)	0	-1.31 – 0.91	0	0	0.66	0	0	0	0	0	0
Sleep (6)	0	-0.91 – 0.45	1	1	0.62	0	0	0	0	0	0
Mobility and movement (9)	2	-0.46 – 0.57	0	0	0.42	0	0	0	0	2	0
Activity (8)	4	-0.30 – 0.56	0	0	0.27	0	0	0	0	0	0
Vitality (6)	0	-0.50 – 0.81	0	0	0.38	1	0	0	0	0	0
Emotional well-being (15)	2	-1.48 – 2.44	0	0	0.86	0	0	0	0	0	0
Self-consciousness (7)	0	-1.27 – 1.02	0	0	0.58	0	0	0	0	0	0
Participation (9)	7	-0.91 – 1.00	0	0	0.57	0	0	0	0	0	0

DIF differential item functioning; HC healthcare; Uni uniform DIF; Non non-uniform DIF.

ISSN: 1477-7525