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

Table 5 Summary of PU-QOL traditional psychometric analysis, field test 2

Scale (No. of items)	Internal consistency Cronbach’s alpha	IIC	Scaling assumptions-corrected ITC	Test retest reproducibility			Convergent validity		Discriminant validity
Scale (No. of items)	Internal consistency Cronbach’s alpha	IIC	Scaling assumptions-corrected ITC	ICC consistency	ICC absolute	Correlation	Related SF12 scale r ¹	PU-QOL HRQL item r ¹(n)	Gender R ²(n)	Age r ²(n)
Pain (8)	0.89	0.24 – 0.66^	0.53 – 0.70^	0.80	0.81	0.80	0.48^b	0.38^b (206)	0.13^b (214)	0.11^b (214)
Exudate (8)	0.91	0.32 – 0.72^	0.51 – 0.75^	0.62	0.63	0.62	n/a	0.25^a (216)	0.08^b (225)	-0.14^b (224)
Odour (6)	0.97	0.72 – 0.93^	0.79 – 0.94^	0.68	0.68	0.70	n/a	0.20^a (217)	0.05^b (228)	-0.14^b (227)
Sleep (6)	0.92	0.49 – 0.81^	0.68 – 0.85^	0.82	0.82	0.82	n/a	0.32^b (171)	0.21^b (178)	0.10^b (178)
Vitality (6)	0.90	0.49 – 0.90^	0.63 – 0.90^	0.74	0.74	0.74	0.36^b	0.52^b (135)	0.03^b (137)	-0.16^b (137)
Movement/Mobility (9)	0.93	0.23 – 0.91^	0.67 – 0.80^	0.87	0.86	0.88	-0.50^b	0.39^b (37)	0.04^b (39)	0.22^b (39)
ADL (8)	0.95	0.41 – 0.90^	0.58 – 0.90^	0.87	0.87	0.87	-0.38^b	0.35^b (48)	-0.05^b (49)	-0.19^b (49)
Emotional well-being (15)	0.94	0.24 – 0.79^	0.54 – 0.76^	0.83	0.82	0.83	-0.44^b	0.58^b (133)	0.16^b (135)	-0.15^b (135)
Appearance & self-consciousness (7)	0.89	0.37 – 0.79^	0.62 – 0.76^	0.81	0.81	0.81	-0.40^b	0.50^b (176)	0.23^b (179)	-0.03^b (178)
Participation (9)	0.93	0.36 – 0.88^	0.60 – 0.86^	0.63	0.64	0.63	-0.52^b	0.51^b (75)	0.01^b (76)	-0.29^b (76)

IIC inter-item correlation; ^Range item-total correlation (ITC); ¹Spearman correlation; ²Pearson correlation; ^aCorrelations falling outside of the predicted range; ^bCorrelations consistent with predictions.

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