Table 4 Item difficulties and discriminatory power of parallel items of both test versions after training

From: Traffic safety knowledge gain of ambulance drivers after simulator-based training

A				B
Item	Difficulty	SD	discriminatory power	Item	Difficulty	SD	discriminatory power
1	12.50	0.33	0.104	12	36.96	0.49	0.145
2^b	10.42	0.31	0.154	17^b	17.39	0.38	0.223
3	89.58	0.31	0.054	18	21.74	0.42	0.242
4	47.92	0.50	0.163	1	52.17	0.51	0.183
5	33.33	0.48	0.001	14	65.22	0.48	0.225
6	37.50	0.49	−0.145	5	30.43	0.47	0.389
7	85.42	0.36	0.070	15	80.43	0.40	0.176
8	33.33	0.48	0.026	11	39.13	0.49	0.051
9^a	89.58	0.25	0.019	6^a	77.17	0.33	0.066
10	50.00	0.51	0.052	4	39.13	0.49	0.071
11	56.25	0.50	0.001	8	45.65	0.50	−0.028
12	22.92	0.42	0.161	7	10.87	0.31	0.165
13	33.33	0.48	0.207	19	17.39	0.38	0.331
14	37.50	0.49	−0.110	2	34.78	0.48	−0.055
15	18.75	0.39	0.003	10	21.74	0.42	0.198
16	22.92	0.42	−0.117	16	30.43	0.47	0.023
17^a	70.00	0.28	0.053	13^a	79.57	0.19	0.115
18	45.83	0.50	0.008	3	43.48	0.50	0.028
19	41.67	0.50	0.143	9	26.09	0.44	0.253

Note: n = 94 participants (intervention group); Number of test item in A matches the number of test B in the same line
^amultiple correct answer options
^bsort answers in right order; rest- five response options, item difficulty is the proportion of people answering the item correctly, that is, the higher the value the easier is the question; item difficulty usually has no unit but describes percentages

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