The Science of Negative Marking: When to Guess and When to Skip
Every major competitive exam—SSC (-0.50), Banking (-0.25), UPSC (-0.66), and Railway (-0.33)—penalizes incorrect answers. Yet, thousands of aspirants lose qualifying rank because of poorly calculated risks.
The Mathematical Expected Value Formula
Suppose an exam gives +2 marks for a correct answer and -0.5 marks for an incorrect answer.
If you blindly guess among 4 choices: Expected Value = (0.25 * 2) - (0.75 * 0.5) = +0.50 - 0.375 = +0.125 marks. While mathematically neutral-to-positive in theory, variance will destroy your score in a 100-question sample.
**If you eliminate 2 options**: Probability of being correct = 50%. Expected Value = (0.5 * 2) - (0.5 * 0.5) = +1.0 - 0.25 = **+0.75 marks** per attempt!
**Rule of Thumb:** If you can confidently eliminate two out of four options, it is mathematically advantageous to attempt the question. If you cannot eliminate at least one option, skip immediately.
Chayantra Academic Research
Editorial Team
