Validation of the Chinese EORTC chronic lymphocytic leukaemia module – application of classical test theory and item response theory

Table 2 Item statistics and internal consistency reliability of QLQ-CLL17

	N	Range	Mean	sd	%Ceiling	%Floor	Internal consistency reliability
	N	Range	Mean	sd	%Ceiling	%Floor	Cronbach’s alpha	Alpha if item deleted	Item-total correlation
							0.92
SB	318	0–100	30.01	17.85			0.81
CLL1	318	1–4	1.68	0.63	2.51	41.82	0.78	0.56	0.62
CLL2	318	1–4	2.00	0.72	3.45	22.01	0.77	0.63	0.74
CLL3	318	1–4	1.82	0.73	2.52	34.28	0.76	0.64	0.75
CLL4	318	1–4	1.78	0.69	2.52	34.91	0.80	0.48	0.52
CLL5	318	1–4	2.22	0.81	5.97	17.92	0.76	0.63	0.70
CLL6	318	1–4	1.88	0.84	6.28	35.53	0.80	0.49	0.53
PC	318	0–100	30.45	19.82			0.85
CLL7	318	1–4	1.66	0.70	2.20	45.28	0.85	0.59	0.64
CLL8	318	1–4	2.15	0.71	5.35	13.21	0.86	0.74	0.80
CLL9	318	1–4	1.88	0.71	1.88	29.56	0.82	0.68	0.74
CLL10	318	1–4	1.95	0.75	4.09	26.10	0.87	0.74	0.81
WF	318	0–100	56.66	26.74			0.91
CLL11	318	1–4	2.75	0.94	27.98	6.92	0.88	0.82	0.86
CLL12	318	1–4	2.88	0.95	34.27	5.97	0.89	0.78	0.83
CLL13	318	1–4	2.78	0.94	28.94	6.29	0.89	0.81	0.85
CLL14	318	1–4	2.64	1.07	30.18	15.41	0.89	0.75	0.80
CLL15	318	1–4	2.94	0.94	35.53	5.35	0.89	0.81	0.85
CLL16	239	1–4	2.36	0.95	15.48	17.99	0.92	0.51	0.56
CLL17	243	1–4	2.56	1.05	25.51	17.28	0.91	0.63	0.68

sd Standard deviation, SB symptom burden, PC physical condition/fatigue, WF Worries/fears about health and functioning