Table 3.

Psychometric Properties of the OKAT by Item

Item Number	Index of Difficulty	Item Discrimination (%)	Item-total correlation	Cronbach's alpha*	Factor Loading
1	0.97	12	0.17	0.69	0.21
2	0.37	63	0.33	0.68	0.42
3	0.43	63	0.34	0.68	0.43
4	0.91	21	0.22	0.69	0.27
5	0.60	67	0.37	0.67	0.46
6	0.20	0.47	0.33	0.68	0.41
7	0.39	35	0.13	0.70	0.15
8	0.27	45	0.27	0.68	0.32
9	0.26	24	0.14	0.70	0.14
10	0.80	17	0.03	0.70	0.03
11	0.12	28	0.21	0.69	0.27
12	0.66	47	0.26	0.68	0.32
13	0.27	53	0.32	0.68	0.37
14	0.67	61	0.34	0.68	0.41
15	0.52	53	0.28	0.68	0.34
16	0.50	70	0.40	0.67	0.46
17	0.24	48	0.30	0.68	0.36
18	0.06	17	0.22	0.70	0.26
19	0.30	60	0.35	0.68	0.42
20	0.29	50	0.27	0.68	0.33

*gives Cronbach's alpha with each item omitted in turn.