9 January 2018

Scored 100 percentile???

All the Indian newspapers are touting the results of CAT exams. Most are running headlines about how 20 students including women and non-engineers have “scored 100 percentile”. See the picture as an example.

Here is my question – as somebody who had to pass CAT long time back – how the heck do you score 100 percentile? I can understand 100 percent. But percentile?

Wasn’t the definition of nth percentile score that n% of the population was lower than the score? (It was strictly less than and not less than or equal to). Which is why I thought we were always taught that you can be 99 percentile… 99.9 percentile… but you can never be 100 percentile (by definition, you could not have scored less than yourself).

So, what gives?

Posted January 9, 2018 by Rajib Roy in category "Musings


  1. By Prasenjit Sarkar on

    No reason for the definition to have changed since our time. Most likely just loose usage of the term (hardly surprising given the abundance of loose reporting).

  2. By Roy K. Cherian on

    Rounded off to 2 decimals. 99.995+ is rounded off to 100, which is fair… But what is unfair is when someone who scored 99.91 doesn’t get a call from A&B, like what happened to my friends daughter!!!

    1. By Roy K. Cherian on

      Mathematically agree with you. But for convenience and conveying the essence of the message to the general public, I think it is ok.

    2. By Roy K. Cherian on

      But % is irrelevant here. The intended message is ‘toppers’ which I think people get it. Yes a lot of people confuse the percentile of CAT with %.

  3. By Vikram Sampat on

    It depends on the reporting of the score. If it is upto 2 decimals then for 100000 and above you will have 5 at 100 so for 250k applicants you will have 12 with 100 percentile

    1. By Rajib Roy on

      You cannot round off in percentile. It runs afoul with the definition of percentile. There is no such thing as 100 percentile.

  4. By Jayashree Patnaik on

    I think CAT percentile is calculated up to three decimal places and is then rounded off to the next closest possible number, i.e 100 %tile effectively means 99.995 and above.

    1. By Abhik Bhowmic on

      That’s ideally true, though the limit still tends to 100 for the top scorers.
      But plz also tell, when the Institute is conducting a national test and the percentile is to be reported correct to 2 places of decimals for all candidates, how will you report a score of a calculated value of 99.995 and above percentile? Possibly they should now try to report values with rounding off correct to 3 or 4 places of decimal in future to avoid reporting of a contradictory 100.


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