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Update (Nov 2026): UPSC CMS is a computer-based test (CBT) — there is no OMR sheet to fill. The mistakes below apply to pen-and-paper (OMR) exams. For UPSC CMS, practise the on-screen interface in the exam simulator instead.
Mistake 1: Bubbling at the Last Minute#
Most common and most dangerous. Bubble every 10-15 questions.
Mistake 2: Wrong Question-Answer Alignment#
Always check Q.No before bubbling. A single shift cascades to 50+ answers.
Mistake 3: Incomplete Erasure When Changing#
Fully erase old bubble. Half-erased marks count as no response.
Mistake 4: Skipping an OMR Row#
After every 25 questions, pause and verify the row number matches your question number.
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Revision history
- 19 September 2026 — Initial publication
- 1 November 2026 — Noted that UPSC CMS is a computer-based test with no OMR sheet; the advice applies to pen-and-paper exams.
Frequently asked questions
Does UPSC CMS use an OMR sheet?
No. UPSC CMS is a computer-based test: you select each answer on screen and there is no OMR sheet to fill. The advice below applies to pen-and-paper (OMR) exams.
What is the most common OMR mistake?
The most common mistake is leaving OMR bubbling until the end. Candidates run out of time and leave questions blank despite knowing the answers. Bubble every 10-15 questions.
Can I change my OMR answer?
Yes — use a soft eraser to fully erase and then fill the new circle completely. A half-erased mark may be read as two answers (both wrong).
What if I skip a question number by mistake?
This is catastrophic — every subsequent answer shifts by one. Stay alert, and during the review pass, verify question numbers match before bubbling.
Related reading
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