NEW DELHI: The merit list for admission to engineering colleges, including Indian Institutes of Technology, through the Joint Entrance Examination - Main (JEE-Main) will be based on percentile scores and not raw marks aspirants scored in the test with the introduction of a two-cycle computer-based examination system from 2019.JEE (Main) is the qualifying examination for those intending to sit for JEE (Advanced) for admission to IITs. As the formats for engineering and architecture courses have changed with tests to be held in January and April, the National Testing Agency (NTA) announced a new procedure for arriving at the NTA score, which will be the basis of the final merit list for admissions to IITs.A senior official of the HRD ministry said the “normalisation procedure based on percentile score” to arrive at the NTA score has been based on the format in practice for the undergraduate-MBBS test conducted by the All India Institute of Medical Sciences, Delhi.“A core group of experts from IITs (Roorkee, Kanpur, Delhi, Guwahati), IIM-Lucknow, NITs, UGC, IASRI (Pusa) and AIIMS, Delhi, among others have been asked to finalise the process for calculating the NTA score,” said the official.From 2019, a JEE-Main aspirant will for the first time have the choice of taking the test twice (January and April cycles). The format will see the test being conducted over a period of around 14 days in each cycle with multiple sessions each day, a device that is intended to significantly reduce the prospects of cheating and manipulation.Explaining the format, an NTA official said, “Candidates will get different sets of questions per session and though efforts will be made to maintain equivalence among various question papers, the difficulty level of question papers in different sessions may not exactly be same.” However, the percentile score of each session is based on the relative performance of students in that particular shift. So the percentile scores of each session will be considered at par.This, the official said, could be as some candidates may end up attempting a relatively tougher set of questions and are likely to get lower marks. But to ensure a level playing field, ‘normalisation procedure based on percentile score’ will be used so that candidates are neither benefitted or disadvantaged due to the difficulty level of the examination.The NTA score will be calculated in multiple steps. Each session will have its NTA percentile score. This means the topper (highest scorer) of each session gets the same percentile of 100 and marks obtained in between highest and lowest scores are converted into appropriate percentiles. Then, apart from the overall percentile, subject-wise (mathematics, physics and chemistry) percentile scores will also be calculated. In order to avoid a bunching effect and reduce tied scores, the percentile scores will be calculated up to seven decimal places.Finally, all percentile scores of different sessions will be merged in one list and the overall merit and ranking will be based on percentile score in descending order. In case of two or more candidates obtaining equal percentile, the “inter-se (among themselves)” merit will be decided in order of candidates obtaining higher percentile score in mathematics, followed by physics, chemistry and finally the candidate older in age. If there is a tie even after this, the candidates will be conferred joint rank.The whole process, the NTA official said, is divided into three steps — distribution of examinees in the sessions randomly so that each session gets approximately equal number of candidates, preparation of results for each session and finally compilation of the NTA score and preparation of the overall merit/rank list.