TABLE 2.

Rasch measurement theory scale level statistics

Concept	Scale	N items tested	N final items	N completed scale	N in RMT	% scored on scale	Chi‐square	DF	P‐value	PSI + extr	PSI − extr	Cronbach alpha + ext	Cronbach alpha − ext	% floor	% ceiling	Missing data
Wound	Assessment	16	11	1008	893	88.6	91.9	88	.37	0.84	0.83	0.92	0.89	1.0	9.7	1.2
	Drainage	10	8	658	574	87.2	74.9	56	.05	0.78	0.76	0.89	0.86	0.9	11.6	5.6
	Smell	9	8	259	211	81.5	22.6	16	.12	0.86	0.84	0.94	0.91	5.0	13.1	7.8
HR‐QOL	Life impact	13	8	998	824	82.6	53.7	72	.95	0.86	0.84	0.93	0.89	3.3	13.2	2.2
	Psychological	17	10	1001	822	82.1	57.0	90	.99	0.85	0.84	0.96	0.95	1.3	15.8	1.9
	Sleep	8	5	461	397	86.1	29.7	20	.07	0.88	0.84	0.93	0.88	9.3	3.9	6.7
	Social	11	5	451	302	67.0	32.5	20	.04	0.80	0.72	0.92	0.80	6.8	27.3	3.8
Treatment	Dressing	9	9	388	262	67.5	49.4	27	.01	0.72	0.75	0.91	0.82	0.2	34.4	11.3
	Suction device	15	9	175	126	72.0	18.7	18	.41	0.87	0.87	0.96	0.92	1.7	21.1	23.9
Experience of care	Information	19	10	337	239	70.9	43.0	30	.06	0.80	0.84	0.95	0.91	0.3	27.5	8.8
	Homecare	21	10	491	226	46.0	52.3	30	.01	0.71	0.83	0.95	0.90	0.6	52.7	6.5
	Wound team	28	10	707	241	34.1	43.1	30	.06	0.52	0.81	0.95	0.91	0.1	62.6	10.0
	Office staff	14	8	662	180	27.2	37.9	16	.00	0.61	0.82	0.97	0.90	0.8	68.4	15.7

Abbreviations: N, number; RMT, Rasch Measurement Theory; DF, degrees of freedom; PSI, person separation index; ext, extremes.