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Table 2 Probabilities of item discrimination and difficulty based on item-writing flaws

From: The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value

Probability (± SE) of creating a discriminating, difficult question (< 80 % correct; > 0.20 discrimination index).

 

NO

YES

Implausible distractors

27.11 % ±8.31

1.83 % ±0.95

Use of all of the Above

13.78 % ±4.23

4.15 % ±2.61

Series of true/false distractors

6.16 % ±2.58

9.54 % ±4.05

Probability (± SE) of creating a poorly discriminating, easy question (> 90 % correct; < 0.15 discrimination index).

 

NO

YES

Implausible distractor

31.66 % ±7.05

81.42 % ±5.35

Series of true/false distractors

64.56 % ±7.38

52.71 % ±9

  1. Some items contained more than one flaw