Item pre-knowledge true prevalence in clinical anatomy - application of gated item response theory model

BMC Medical Education

Table 2 Data description according to CTT

Year	Period	N	Reused (N)	Difficulty^a,c Mean (SD)	Discrimination^b,c Mean (SD)	Cronbach’s Alpha	ω_h	ω_t
2008	1	217	0	0.57 (0.18)	0.37 (0.19)	0.88	0.46	0.89
2008	2	123	4	0.63 (0.20)	0.32 (0.17)	0.86	0.51	0.87
2009	1	208	13	0.66 (0.20)	0.34 (0.13)	0.88	0.48	0.88
2009	2	113	6	0.64 (0.21)	0.37 (0.16)	0.89	0.38	0.90
2010	1	192	26	0.64 (0.20)	0.30 (0.14)	0.86	0.44	0.87
2010	2	116	13	0.59 (0.21)	0.32 (0.15)	0.87	0.41	0.88
2011	1	243	21	0.62 (0.22)	0.37 (0.17)	0.89	0.56	0.90
2011	2	48	14	0.59 (0.20)	0.37 (0.19)	0.90	0.36	0.91

^a% of students who correctly answered the item
^b Biserial correlation between the item and the number of correct answers to the other items
^c To assess whether there were significant differences between the examinations, in the difficulty and discrimination indexes, mixed effect models were used with a fixed factor (examination) and the item-level random intercept to account for the residual correlation within the same (reused) items

ISSN: 1472-6920