Table 2.

Psychometric characteristics of the patients as assessed according to the 12 items on the SMSS

SMSS items	Hi	Discriminationa	Informationa	CFA standardized coefficients
1	0.572	2.039	5.89	0.722
2	0.618	2.459	8.17	0.783
3	0.623	2.685	8.34	0.793
4	0.644	3.041	11.25	0.833
5	0.629	2.504	8.65	0.784
6	0.593	2.444	6.28	0.757
7	0.634	2.458	8.84	0.803
8	0.579	2.155	6.87	0.724
9	0.585	2.039	6.40	0.738
10	0.658	2.828	11.53	0.821
11	0.528	1.716	5.32	0.647
12	0.557	1.902	5.82	0.696

CFA Confirmatory factor analysis, H_i Scalability coefficient

^aDiscrimination and information coefficients were from Samejima’s Grade Response Model [14]