IITs are premier engineering institutions in the country. The undergraduate program at IITs is highly sought after, with more than ten lakh students competing for around ten thousand seats every year. There is a two-tier examination for admission — JEE Main followed by JEE Advanced.
JEE Main examination is used for admission to other engineering colleges, as well as shortlisting students for JEE Advanced. Admission to different engineering streams across IITs is determined by the rank obtained in JEE Advanced.
Considered one of the toughest examinations in the word, JEE Advanced is administered to approximately 2 lakh students every year of which around ten thousand (the top five per cent) are selected for admission.
An oft-repeated critique of JEE Advanced is that it is too difficult, even compared to JEE Main. For example, in 2021, the last admitted student to the IITs, with a rank around twelve thousand, scored only 30 per cent marks in the examination.
Further, more than half the students scored less than 10 per cent marks. Why has the examination not been made easier for students is a question posed by many.
Is it because those setting the papers are unable to design easier questions? Or because they derive some kind of pleasure in making a large number of students perform poorly? The answer is none of the above. The requirement of identifying and ranking the top five per cent of the students forces the examination to be tough, as I explain below.
Let us consider a hypothetical situation first. Suppose one has to conduct an examination for two lakh students with an aim of evaluating their knowledge and understanding. Typically, in a large set like this, abilities of students will follow a bell-shaped curve – large numbers in the middle (corresponding to in-between abilities), and the numbers tapering off as the abilities become higher or lower than average.
In Statistics, this is referred to as Normal Distribution. An ideal examination for identifying the level of students would be one in which the average score is 50 (out of 100), so that 0 marks represent very poor level, 50 marks represent average level, and 100 marks represent very high level.
But JEE Advanced has a different aim – to identify the top five per cent students from the given set of two lakh students(that have appeared qualified JEE Main).
If an examination as above is conducted in JEE Advanced, then all the students in top 5 per cent will have more than 80 marks (under certain reasonable assumptions about standard deviation of the curve).
This makes it difficult to rank them since all the ten thousand students are compressed within a band of 20 marks (there will be 500 students on average on each mark in the band).
Even if one uses tie-breaking criteria by using marks in different subjects, it will still bunch a large number of students on the same marks.
The band of marks 0-80 gets wasted since all eligible students are within the band 90-100. Ideally, one would like to use the entire band of 0-100 for top ten thousand students – this can happen when all except top ten thousand get zero marks.
Of course, this is not possible in practice. But a sufficiently tough examination comes close to achieving the ideal by increasing the band of top 5 per cent students. And that is why the JEE Advanced is so tough — the high difficulty expands the top 5 per cent band significantly (30-100 in the year 2021).
In fact, JEE Main exam also follows the same principle. In 2021, the top five per cent students in JEE Main occupied the band 30-100, almost exactly the same as JEE Advanced.
It is done for the similar reason: to identify top 5 per cent students (around fifty thousand) out of ten lakh for admission in various engineering colleges across the country.
One may then ask — why is JEE Advanced more difficult than JEE Main? The reason is that JEE Advanced needs to identify the top 5 percent of the set shortlisted through JEE Main, which is the top 1 percent of the candidates writing JEE Main. So one needs a large band for the top 1 percent of this set, forcing the JEE Advanced to be tougher than the JEE Main.
Courtesy : The Indian Express