WHAT IS A PERCENTILE?

A percentage is a straightforward measure of how much a student scores out of the total possible marks. A percentile, on the other hand, is a relative measure

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On June 14, the results of the NEET-UG, India's most competitive medical entrance examination, were declared. Among over 22 lakh candidates, Mahesh Kumar, a student from Rajasthan, stood out with a score of 686 out of 720. Yet, his percentile was reported not as 100 but as 99.9999547. This number may seem puzzling. Why is the national topper in the country not awarded a 100th percentile? What does percentile mean anyway? As lakhs of students await their ranks and counselling, it becomes important to decode the mathematics behind this misunderstood metric.

A percentage is a straightforward measure of how much a student scores out of the total possible marks. For example, Mahesh's 686 out of 720 translates to roughly 95.27%. Based on the questions answered, it is an absolute measure, showing how much a student knew. A percentile, on the other hand, is a relative measure. It tells us how a student performed compared to others. A 99 percentile means the student did better than 99% of the test-takers. It doesn't say how much the student scored, but where they stand in the crowd.

This distinction becomes crucial in exams where lakhs of candidates participate. In competitive exams, especially those with a vast number of candidates, a small difference in marks can translate into thousands of ranks.