Notice on Normalization Methodology for Computer Based Test (CBT) Exams for All Centralized Employment Notices (CENs)

It is notified for all concerned that the following normalization methodology for scores/marks shall be followed by Railway Recruitment Boards (RRBs) for normalizing the raw scores of candidates in examinations conducted in multiple shifts. For this, the RRB shall use the percentile equivalence.

Percentile Scores Explained

1. Percentile Scores: These are scores based on the relative performance of all those who appear for the examination. The marks obtained are transformed into a scale ranging from 100 to 0 for each shift. The Percentile Score is not the same as the percentage of marks obtained.

2. 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. The topper (highest score) of each shift will get a Percentile of 100.

3. The Percentile Score will be the Normalized Score for the examination (instead of the raw marks) and shall be used for the preparation of merit lists.

4. The Percentile Score of a Candidate for a particular shift will be calculated as follows: Percentile Score = (Number of candidates appeared in the ‘Shift' with raw score EQUAL TO OR LESS than the candidate / The total number of the candidates who appeared in the 'Shift') x 100

5. The Percentile Scores for the raw score of all candidates for all shifts would be merged and shall be called the RRB Scores (or RRC scores for Level-1 Exam), which will then be used for compiling results and deciding merit allocation.

6. Percentile Scores will be calculated up to 5 decimal places to avoid bunching and reduce ties.

7. In case of a tie in Percentile Score, the merit position shall be determined by age criteria (older person placed higher). If the age is also the same, then the alphabetical order (A to Z) of the name will be used to break the tie.

Finalization of Merit and Normalized Marks

To finalize the Merit list based on the Percentile Score, candidates must secure the Minimum Percentage of Marks as per the qualifying criteria given in the CENs for their respective categories:

• UR: 40%
• EWS: 40%
• OBC (Non-creamy layer): 30%
• SC: 30%
• ST: 25% (30% for Level-1 Exam)

Calculation of Normalized Marks

Selection of Base Shift: The "Base Shift" is the shift with the “Highest Mean" (Average) among all shifts, provided its candidate count is 70% or more of the average of all shifts. In case of a tie in the "Highest Mean," the shift with the "Highest Individual Marks" is chosen. If both are tied, the shift with the “Highest Present Count” is selected as the Base Shift.

Interpolation Formula: X is the percentile score of a candidate. If X is found in the Base Shift, the corresponding Normalized Marks (N) are directly available. Otherwise, the following interpolation formula is used:

• a) For candidates whose Percentile Score is greater than or equal to the minimum percentile of the Base Shift: N = ((Y2-Y1) / (X2-X1) * (X-X1)) + Y1 Where:

  • N = Normalized Marks
  • X2 = immediate higher Percentile Score in Base Shift
  • X1 = immediate lower Percentile Score in Base Shift
  • Y2 = marks corresponding to X2 Percentile Score in Base Shift
  • Y1 = marks corresponding to X1 Percentile Score in Base Shift

• b) For candidates whose Percentile Score is less than the minimum percentile of the Base Shift: N = Y1 - (((Y2-Y1) / (X2-X1)) * (X1-X)) Where:

  • N = Normalized Marks
  • X1 = immediate higher Percentile Score in Base Shift
  • X2 = immediate next higher Percentile Score in Base Shift
  • Y1 = marks corresponding to X1 Percentile Score in Base Shift
  • Y2 = marks corresponding to X2 Percentile Score in Base Shift

Candidates are advised to refer only to the official websites of RRBs for updates. RRB selections are based on Computer Based Test (CBT) and recruitment is based only on merit.