Negative Marking: When to Guess and When to Leave It

The arithmetic

A four-option question, one mark for a correct answer, a third off for a wrong one. Guess blind and you are right one time in four: one mark gained once, a third lost three times, a net loss. Blind guessing loses, and that is by design.

Now eliminate one option. You are right one time in three: one mark gained once, a third lost twice — which comes out to nothing. One elimination makes guessing break even. Eliminate two and it is clearly worth answering.

So the rule is not about confidence in the abstract. It is about elimination: if you can rule out even one option with a reason, answering is at worst free.

A feeling is not an elimination

The trap is that a half-remembered fact feels like an elimination. "It is probably not that one" is not the same as "that one is from a different decade". The first is noise; the second is information. Our reports type a wrong answer partly by how long you spent on it, because a fast wrong answer and a slow wrong answer are different mistakes needing different fixes.

Do not decide this in the hall

Candidates who handle negative marking well have already chosen their rule and simply apply it. The ones deciding question by question spend the paper negotiating with themselves, and that costs far more marks than the deductions do.