Multiple choice questions are typically graded using one of two primary methods: positive marking or negative marking.
Positive Marking
- Concept: The most common method. Each correct answer earns a predetermined point value (usually one point), while incorrect or unanswered questions receive no points.
- Calculation: The total score is simply the sum of the points earned for correct answers.
- Example: If a test has 20 multiple choice questions worth 1 point each, and a student answers 15 correctly, their score is 15.
Negative Marking
- Concept: Less common but used in some high-stakes exams. Correct answers receive points, but incorrect answers incur a penalty (negative points). Unanswered questions typically receive zero points.
- Rationale: Designed to discourage guessing and to more accurately reflect a student's true knowledge. This principle is also known as "correction for guessing."
- Calculation: The total score is calculated as (Number of Correct Answers Points per Correct Answer) - (Number of Incorrect Answers Penalty per Incorrect Answer).
- Example: Suppose a test has 20 questions, with 1 point for a correct answer and a -0.25 penalty for an incorrect answer. A student answers 15 correctly and 5 incorrectly. Their score is (15 1) - (5 0.25) = 15 - 1.25 = 13.75.
- Penalty Variations: The penalty for incorrect answers can vary. Common penalties are fractions of the points awarded for a correct answer (e.g., -0.25, -0.33, or -0.5 points).
Table Summarizing Grading Methods
| Grading Method | Correct Answer | Incorrect Answer | Unanswered Question | Purpose |
|---|---|---|---|---|
| Positive Marking | + Points | 0 Points | 0 Points | Simple scoring; rewards correct answers |
| Negative Marking | + Points | - Points | 0 Points | Discourages guessing |
Conclusion
In summary, multiple choice questions are graded either by simply awarding points for correct answers (positive marking) or by awarding points for correct answers while subtracting points for incorrect answers (negative marking, to discourage guessing). The specific method depends on the test's goals and design.
