NTA is conducting examinations on multiple dates, generally in two sessions per day. The candidates are given different sets of questions per session and it is quite possible that in spite of all efforts of maintaining equivalence among various question papers, the difficulty level of these question papers administered in different sessions may not be exactly the same.
Some of the candidates may end up attempting a relatively tougher set of questions when compared to other sets. The candidates who attempt the comparatively tougher examination are likely to get lower marks as compared to those who attempt the easier one. In order to overcome such a situation, Normalization procedure based on Percentile Score is used for ensuring that candidates are neither benefited nor disadvantaged due to the difficulty level of the examination.
With the objective of ensuring that a candidate’s true merit is identified, and that a level playing field is created in the above context, the Normalization Procedure, set out below is adopted, for compiling the NTA scores for multi session papers.
The process of Normalization is an established practice for comparing candidate scores across multi session papers and is similar to those being adopted in other large educational selection tests conducted in India. For normalization across sections, NTA uses the percentile equivalence.
Percentile Scores: Percentile scores are scores based on the relative performance of all those who appear for the examination. Basically the marks obtained are transformed into a scale ranging from 100 to 0 for each session of examinees.
The Percentile Score indicates the percentage of candidates that have scored equal to or below (same or lower raw scores) that particular percentile in that examination. Therefore the topper (highest score) of each session will get the same percentile of 100 which is desirable. The marks obtained in between the highest and lowest scores are also converted to appropriate percentiles.
The percentile scores are calculated up to 7 decimal places to avoid bunching effect and reduce ties.
Highest Raw Score and Percentile Score: All the highest raw scores have normalized Percentile Score of 100 for their respective session.
Method of Resolving Ties
The overall merit or ranking is based on the percentile scores of the total raw scores. In case of two or more candidates obtaining equal percentile scores in the test, the inter-se merit of such candidates shall be determined in order of preference as follows:
- Candidates obtaining higher Percentile Score in Mathematics in the Test.
- Candidates obtaining higher Percentile Score in Physics in the Test.
- Candidates obtaining higher Percentile Score in Chemistry in the Test.
- Candidates older in age to be preferred.
Procedure for Normalization and Preparation of Rank List
Step 1: Distribution of examinees in two days and in two shifts per day
Candidates would be distributed into four sessions randomly so that each session has approximately equal number of candidates. These four sessions would be as follows:
- Session-1: Day-1 Shift-1
- Session-2: Day-1 Shift-2
- Session-3: Day-2 Shift-1
- Session-4: Day-2 Shift-2
In the event of more number of days or more number of shifts, the candidates are divided accordingly.
This will ensure that there is no bias in the distribution of candidates who take the examination.
Step 2: Preparation of Results for each Session
The examination results for each session would be prepared in the form of
- Raw Scores
- Percentiles Scores separately for each of the three subjects (Mathematics, Physics, Chemistry) and the total
Let T1, M1, P1, C1 be the raw scores in Total, Mathematics, Physics, Chemistry of a candidate and T1P, M1P, P1P, C1P be the Percentile Scores of Total, Mathematics, Physics, Chemistry of that candidate.
Step 3: Compilation of NTA score and Preparation of Overall Merit/Rank List
The percentile scores for the total raw score for all the four sessions would be merged and is called the NTA scores which is then used for compilation of result and preparation of overall Merit List / Ranking.
The Percentile of all four sessions is calculated separately for the total raw score and the raw scores in three subjects (Mathematics, Physics, and Chemistry).