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. 2015 Sep 8;4(5):244–251. doi: 10.1007/s40037-015-0212-x

Table 3.

Summary of psychometric characteristics before and after intervention in experiment and control group. Result of Fisher’s exact analysis is also shown in select cells

Subgroup A (removal of IWFs + enhancement of CL) Subgroup B (replacement or removal of NFDs) Control group
Before After Before After Before After
# of items 21 21 11 11 23 23
Average # of distractors per MCQ 3.62 3.62 3.73 3.55 3.48 3.48
Total # of distractors 76 76 41 39 80 80
Total # of FDs 14 (18 %) 17 (22 %) 10 (27 %) 12 (33 %) 23 (29 %) 22 (28 %)
Mean # of FDs 0.67 0.81 0.91 1.09 1 0.96
Average difficulty 0.86 0.85 0.85 0.8 0.84 0.83
Average pbi 0.05 0.19 0.04 0.19 0.05 0.06
# of MCQs with moderate difficulty 5 5 3 4 (9 % increase; df [1], p > 0.05) 10 12 (8 % increase; df [1], p > 0.05)
# of MCQs with sufficient discriminatory ability 0 10 (47 % increase; df [1], p < 0.05) 0 6 (56 % increase; df [1], p < 0.05) 0 0

CL cognitive level, FDs functioning distractors, IWF item-writing flaws, MCQ multiple-choice questions, NFDs non-functioning distractors, pbi point-biserial correlation.