Negative marking in the UPSC Preliminary Examination plays a crucial role in assessing candidates' accuracy and decision-making abilities. For every incorrect answer, a certain percentage of marks are deducted, which discourages random guessing and encourages candidates to be more cautious and knowledgeable in their responses. This system ensures that only those with a solid understanding of the syllabus progress to subsequent stages. It emphasizes the importance of thorough preparation and strategic answering, as candidates are incentivized to focus on accuracy rather than attempting every question without certainty.