Psychometric properties of the end-of-life care decision inventory (EOL-CDI): a mixed-methods study

Table 3 Initial item analysis of EOL-CDI (29 items) (N = 238)

Items	Mean ± SD	Item difficulty index		Discrimination index
Items	Mean ± SD	CTT	IRT	CTT	IRT
EOL-CDI item 1	0.97 ± 0.18	0.97	− 3.17	0.10	1.35
EOL-CDI item 2	0.90 ± 0.30	0.90	− 2.81	0.24	0.91
EOL-CDI item 3	0.94 ± 0.24	0.94	− 2.52	0.16	1.48
EOL-CDI item 4	0.47 ± 0.50	0.48	0.98	0.18	0.10
EOL-CDI item 5	0.69 ± 0.46	0.69	− 2.81	0.26	0.29
EOL-CDI item 6	0.63 ± 0.48	0.63	− 3.77	0.23	0.15
EOL-CDI item 7	0.76 ± 0.43	0.76	− 4.70	0.25	0.25
EOL-CDI item 8	0.32 ± 0.47	0.32	− 6.30	0.06	-0.12
EOL-CDI item 9	0.86 ± 0.35	0.86	− 2.76	0.23	0.71
EOL-CDI item 10	0.76 ± 0.43	0.77	− 2.35	0.26	0.53
EOL-CDI item 11	0.39 ± 0.49	0.39	2.14	0.27	0.22
EOL-CDI item 12	0.87 ± 0.33	0.87	− 2.72	0.23	0.79
EOL-CDI item 13	0.96 ± 0.20	0.96	− 2.52	0.14	1.87
EOL-CDI item 14	0.52 ± 0.50	0.52	− 0.14	0.42	0.47
EOL-CDI item 15	0.71 ± 0.45	0.71	− 3.12	0.28	0.30
EOL-CDI item 16	0.63 ± 0.48	0.63	− 0.39	0.67	1.78
EOL-CDI item 17	0.82 ± 0.39	0.82	− 1.07	0.57	2.59
EOL-CDI item 18	0.50 ± 0.50	0.50	0.06	0.54	1.04
EOL-CDI item 19	0.11 ± 0.31	0.11	3.50	0.24	0.66
EOL-CDI item 20	0.45 ± 0.50	0.45	0.26	0.66	1.25
EOL-CDI item 21	0.17 ± 0.38	0.17	2.80	0.25	0.60
EOL-CDI item 22	0.74 ± 0.44	0.74	− 0.69	0.74	2.59
EOL-CDI item 23	0.73 ± 0.45	0.73	− 0.81	0.51	1.66
EOL-CDI item 24	0.71 ± 0.45	0.71	− 0.82	0.61	1.40
EOL-CDI item 25	0.79 ± 0.41	0.79	− 1.04	0.60	2.03
EOL-CDI item 26	0.53 ± 0.50	0.53	− 0.10	0.56	1.05
EOL-CDI item 27	0.41 ± 0.49	0.41	0.47	0.61	0.97
EOL-CDI item 28	0.29 ± 0.46	0.29	0.90	0.57	1.31
EOL-CDI item 29	0.73 ± 0.45	0.73	− 0.78	0.66	1.77
Mean		0.63	− 1.18	0.38	1.03
SD			2.20		0.73

SD standard deviation, EOL-CDI end-of-life care decision inventory, ITC item-total correlation, CTT classic test theory, IRT item response theory

ISSN: 1477-7525