MCQ Item Analysis Calculator
The MCQ item analysis calculator gives examiners a complete statistical view of a test question. Enter the total students and the upper and lower 27% correct counts to get difficulty, discrimination, and point-biserial correlation.
How It Works & Formula
Item difficulty is P = (upper + lower) / (2 x n27). Discrimination is D = (upper - lower) / n27. The point-biserial correlation rpbis = D x sqrt(p x q) estimates how well the item predicts overall performance.
Frequently Asked Questions
What is item analysis used for?
Item analysis evaluates the quality of test questions by measuring difficulty and how well each question discriminates between strong and weak students.
What is point-biserial correlation?
It is a measure of the relationship between a dichotomous variable (correct or incorrect answer) and a continuous variable (total test score).
Should I remove poorly performing items?
Items with very low discrimination or extreme difficulty should be reviewed, revised, or removed to improve test reliability.