Teachers · Exams
Item analysis: difficulty, discrimination and distractors
The “Per-question analysis” tab on the results page shows which questions are too easy, too hard, poor at separating stronger and weaker students, or have wrong options almost nobody picks — so you can review your exam.
Published October 11, 2026 · Last updated October 15, 2026
Steps
- Open the exam's “Scores” → “Per-question analysis” tab. The table has extra columns: “Difficulty (p)”, “Discrimination (D)”, “Warnings” and “Option”.
- Reading p: the share of attempts that got the question right (blank counts as wrong), from 0 to 1. Reading D: p for the top 27% of attempts by score minus p for the bottom 27%. A negative D is shown in red; below D you see the correct rate of both groups.
- Click “Option” to see each choice: the correct option, how many attempts chose it, the choice rate, and how many attempts in the top and bottom groups chose it.
- Tick “Show only questions to review” to keep only questions with warnings. Open “How to read warnings” to see what each warning label means.
- The “Competency & difficulty matrix” tab also has a “Performance by tag” table: the achievement level for each question tag, with the weakest tag at the top and untagged questions at the bottom.
Options and limits
- Too easy
- p ≥ 0.90: almost every candidate got it right.
- Too hard
- p ≤ 0.20: very few candidates got it right.
- Negative discrimination
- D < 0: the low-scoring group got it right more often than the high-scoring group — check the answer key.
- Low discrimination
- 0 ≤ D < 0.20: the question doesn't separate the high-scoring and low-scoring groups well.
- Weak distractor
- A wrong option was chosen by fewer than 5% of the candidates who answered. This is only checked when at least 10 attempts have answered the question (chosen an option).
- Only fully graded Test mode attempts are counted. Practice attempts aren't counted because students saw right and wrong answers while working; when attempts are excluded, the page says “Excluded … Practice-mode attempts…”.
- You need at least 10 Test mode attempts to calculate D and flag questions. Until then, the D column is left blank, no question is flagged, the “Show only questions to review” box is hidden, and the page shows how many attempts there are.
- Only single-answer, multiple-answer and True/False questions have p, D and an options table. Figures are counted per attempt: if the exam allows several attempts, one student can have several.
- For multiple-answer questions, one attempt can pick several options, so the choice rates can add up to more than 100%.