Railway Recruitment Board (RRB) conducts several examinations at Pan India level every year. This is why it attracts exceptionally large number of candidates every year and thereby increasing the number of applicants. In order to take examination for such a large number of candidates, examination has to be split in various sessions keeping in view the limitations of the capacity of examination venues available across the country. For example, CEN 02.2018 for Level 1 post had attracted 1.89 Crore candidates and the examination was conducted in 153 sessions. RRB applies normalization method for calculating the qualifying marks of an examination conducted in multiple sessions having different difficulty level of the questions. Let us look in detail how the normalization of marks will be done in RRB NTPC, RRB Group D Level-1 and RRB Ministerial & Isolated (MI) Categories 2020 Railway Exams.
Normalization of Marks: RRB NTPC, RRB Group D (Level-1) & RRB MI 2020 Railway Exams
Normalization process followed by RRBs is a scientific and statistical process. It is not a process of awarding grace marks. It completely depends on the statistical parameters calculated based on the performance of candidates in the session of the candidates as well as candidates of other sessions. The process involves raw score of the candidate, mean and standard deviation of raw marks of candidates in his/her session as well as other sessions being normalized.
Formula for Normalization Method - The normalisation formula used by RRBs is as under:
Formula for Calculating Raw Score - The Raw Score is computed as under:
Total Questions-100; No of Questions Ignored (question wrong, multiple options correct etc): 2
No of Questions attempted: 60; Correctly Answered: 54; Wrongly Answered: 6
Positive Marks: 54; Negative Marks: 2; Net Score: 54-2=52
Score Out of 100: (52/98)*100= 53.06
Raw Score= 53.06
So, the raw score of different candidates are different and as mentioned earlier, the raw score of candidate is also one of the parameters in the calculation. So, increase/ decrease of one candidate may differ from increase/decrease of another candidate in the same session.
Deciding Base Session - In the statistical process, statistical parameters of a session e.g. mean marks and standard deviation of marks scored by the candidates in the session are analysed and based on the calculated values of these parameters a session is taken as base session. The normalization is carried out with respect to this base session so as to equalize the difficulty level of all other sessions to this session. Among sessions having 70% and above the average attendance of all sessions, the one with maximum value of Mean of raw score is taken as base session.
For Example: Consider In examination which is conducted in 9 sessions and the statistical parameters of the sessions are as under:
Here, Session No 7 is taken as base session based on the mean of raw marks.
Now, Consider a candidate of Session 8, whose raw marks are 75.
So, the normalized marks of the candidate will be 115.89 which surely differs from his/her raw score. Therefore, the normalized score can either be more or less than the raw score obtained by the candidate in an RRB Examination. The normalization process is completely statistical/ mathematical and there is no discretion/human intervention whatsoever. So, whenever Computer Based Tests (CBT) or Offline Exams are conducted in multiple sessions by RRB, the raw marks obtained by the candidates in different sessions will be converted to normalized marks for fair assessment and selection process.