Table 3.

Psychometric indices by flaw areas with and without rule 4 (“Keep the content of each item independent from content of other items on the test”)

Flaw areas	Number of items N (%)	Difficulty Index Mean (SD)	Discrimination Mean (SD)
Standarda	354 (45.8)	0.65 (0.21)	0.36 (0.17)
Content concernsb	56 (7.2)	0.63 (0.18)	0.36 (0.16)
Content concerns without rule 4b	12 (1.6)	0.61 (0.22)	0.25 (0.15)
Style concernsb	47 (6.1)	0.62 (0.20)	0.35 (0.14)
Writing the stemb	150 (19.4)	0.59 (0.19)	0.31 (0.14)
Writing the choicesb	166 (21.5)	0.60 (0.21)	0.33 (0.15)

^a3/4 reviewers considered that the item had no IWF

^b3/4 reviewers considered that at least one item had IWF from this category