Myth 1: "Every wrong answer costs you a full mark"
What people say: Get one wrong and you lose a mark; get four wrong and you have wiped out four correct answers.
What the notification says: There will be a penalty for wrong answers in the objective-type question papers. One-third of the marks assigned to that question is deducted as a penalty. Not one mark. One-third of whatever that particular question is worth.
Why the myth persists: It is a reasonable-sounding simplification, and in state-level examinations with one-mark questions it is sometimes literally true. Repeated often enough, the simplification became the rule.
What follows in practice: The penalty is proportional. A question worth two marks costs you roughly 0.66 for a wrong answer, not 1. That is a materially different arithmetic from the one most candidates are carrying into the hall, and it changes when a guess is worth making. Which brings us to the next myth, which is the important one.
Myth 2: "There are 100 questions of 2 marks each in Paper I, so the penalty is exactly 0.66"
What people say: Paper I has 100 questions at 2 marks each; Paper II has 80 questions at 2.5 marks each; therefore the penalties are 0.66 and 0.83.
What the notification says: Nothing. This is the point of the post. The notification does not state a question count for either paper. It states that each paper carries a maximum of 200 marks and is of two hours' duration, and that the penalty is one-third of the marks assigned to the question. It does not tell you how many questions there are, and therefore it does not tell you what any individual question is worth.
Why the myth persists: Because the figures happen to describe recent papers, and because every coaching website publishes them as though they were notified. They are an observation about past question papers, not a rule. The distinction matters the moment the Commission changes the composition of a paper, which it is under no obligation to announce in advance.
What follows in practice: If you want the question count and per-question value for a given year, take it from that year's actual question paper, which the Commission publishes in its previous-year papers archive →. Do not take it from a table on a coaching site, including this one. What you can rely on, permanently, is the ratio: the penalty is one-third of the question's value, whatever that value turns out to be.
Myth 3: "If you can eliminate two options, always guess"
What people say: Down to two options, it is a coin flip with a favourable payoff, so mark it.
What the notification says: The notification does not give strategy advice. It gives you the mechanism, and the mechanism does favour a two-option guess. If a question is worth m marks, a correct answer is +m, a wrong answer is −m/3. At a genuine fifty-fifty, the expected value of guessing is (0.5 × m) + (0.5 × −m/3), which is +m/3. Positive. Even at one-in-three, the expected value is (0.33 × m) + (0.67 × −m/3), which is still marginally positive. At a blind one-in-four it is zero.
Why the myth persists: Because the arithmetic is correct. The myth is not the arithmetic; it is the word "genuine".
What follows in practice: The calculation assumes your elimination is sound. On a well-constructed Prelims question the distractors are built to be eliminated by a candidate who has half-learnt the topic, so the two options you are left with are frequently the two the examiner intended you to be left with, and your fifty-fifty is closer to thirty-seventy against. The arithmetic favours guessing; your self-assessment is the unreliable part. Log every guess in a mock and score the guesses separately from the answers you knew. If your guesses convert below fifty per cent, the arithmetic has stopped working for you personally.
Myth 4: "Marking two options gives you a better chance"
What people say: If you are torn, darken both circles and you improve your odds.
What the notification says: Explicitly, and there is no ambiguity: if a candidate gives more than one answer, it will be treated as a wrong answer, even if one of the answers given happens to be correct. The same penalty applies.
Why the myth persists: It is the kind of thing somebody invents once and nobody bothers to check, because it is intuitively attractive and because you never find out that it did not work.
What follows in practice: One mark per question. Also, and relatedly, an incompletely erased answer on an OMR sheet can read as two answers. That is not a rule of the examination, it is a property of optical scanning, and it is the reason to carry a proper eraser and to check your sheet before you hand it over.
Myth 5: "A blank answer is penalised" — and its twin, "CSAT is qualifying so you can guess freely"
What people say: Two claims, both wrong in different directions. First, that leaving a question unattempted attracts some penalty. Second, that because Paper II only needs 33 per cent, negative marking there does not really matter.
What the notification says: On blanks, it is direct: if a question is left blank, that is if no answer is given by the candidate, there will be no penalty for that question. On CSAT, two separate facts: It is a qualifying paper with minimum qualifying marks fixed at 33 per cent. And it is mandatory for a candidate to appear in both papers — a candidate who does not appear in both is disqualified. The penalty provisions apply to the objective-type papers, which is both of them.
Why the myth persists: The first is straightforward misinformation. The second is a misreading of "qualifying": candidates hear that the marks do not count towards merit and conclude that the marks do not matter. They do not count towards your rank. They absolutely decide whether you have a rank.
What follows in practice: Blank is a legitimate strategic choice and the only zero-cost option on the paper. And a candidate who guesses recklessly through CSAT on the theory that 33 per cent is easy can, by accumulating penalties, land below 33 per cent — at which point their Paper I performance becomes irrelevant, because the merit list for Prelims is drawn on 33 per cent in Paper II plus the qualifying mark in Paper I.
What the notification does not settle
Three things, and it is worth being explicit about all three:
- It does not state the number of questions in either paper, or the marks per question: Take those from the actual papers in the official archive, year by year.
- It does not state whether the penalty is applied before or after any rounding of the total: Nothing in the public documents examined addresses it, and no coaching site's answer is sourced either.
- And it does not tell you what the Paper I qualifying mark will be: The notice says the Prelims merit list is drawn on 33 per cent in Paper II together with the total qualifying marks in Paper I as may be determined by the Commission. That is decided after the paper. Anyone quoting you a target score for next year is guessing. Historical cut-offs are published on the Commission's cut-off page; reading them without misleading yourself is treated on our page on the UPSC examination pattern →.
What to do with all of this
- 1. Recalculate your risk threshold using one-third, not one: Most candidates are guessing too conservatively because they are working from the wrong penalty.
- 2. Score your guesses separately in every mock: Two numbers: how many you attempted on elimination, and how many of those were right. If that conversion rate is below fifty per cent, guess less. If it is above sixty, guess more. This is the single most useful piece of data you can generate about your own paper, and almost nobody generates it.
- 3. Never mark two options: There is no version of the arithmetic in which it helps.
- 4. Treat CSAT with the same discipline as Paper I: Qualifying is not the same as easy.
- 5. Read the penalty note in the notification yourself: It is two paragraphs.
Point two changes scores and it is the one you cannot do alone with a book. It needs papers taken under time, marked consistently, with the analysis structured so your guesses are visible as a separate population. Our Prelims Test Series → reports attempt and accuracy separately so that you can see your guessing conversion rather than infer it.
Frequently asked
How much is deducted for a wrong answer in UPSC Prelims?
One-third of the marks assigned to that question. Not one full mark, and not a fixed figure — it is proportional to the question's value.
Is there negative marking in CSAT?
Yes. The penalty provisions apply to the objective-type papers, and both Prelims papers are objective type. CSAT being a qualifying paper does not exempt it.
Is there a penalty for leaving a question blank?
No. The notification states plainly that a question left blank attracts no penalty.
Does marking two options count as one attempt or a wrong answer?
A wrong answer, and the penalty applies, even if one of the marked options is correct.
How many questions are there in Prelims Paper I?
The notification does not say. It states 200 marks and two hours per paper. For a specific year, count the questions in that year's paper in the Commission's previous-year papers archive.