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Natural Sciences Tripos

 

Marking and Classing

The following marking scheme has been approved by the Committee of Management for the Natural Sciences Tripos.

Introduction

Examiners are nominated by the various Faculties and Departments who contribute to teaching on the Tripos and are formally appointed by the General Board. In each subject, there is a Senior Examiner and other appointed Examiners and Assessors who are responsible for setting the papers and marking the scripts. There is also a Chair of Examiners who, along with the Senior Examiners, assigns classes to candidates and produces the class list and final markbooks.

Marks and classes in individual subjects

In each subject, the Examiners produce a mark out of 100 for each candidate using the local subject examination processes which may include necessary scaling.  Whilst the whole cohort of students taking a particular subject is ranked, including those from other Triposes, subject rankings are not used to calculate the percentile rankings and so are not involved in establishing the order of merit.

There are targets for class distributions in individual subjects.  The default target distribution is such that 60% of all candidates taking all papers of a subject shall obtain marks of 60.0 or above and 20% of all candidates taking all papers of a subject shall obtain marks of 70.0 or above.

The candidates will also be given both a Class in each subject and a value which indicates their position within the rank order of candidates in each subject.  This rank statistic will be a percentile rank, such that the candidate with 100% is the one with the highest mark and that with 0% the one with the lowest mark; all other candidates will fall between these values, the interval being determined by the number of candidates.  The Subject Class of each candidate will reflect their final subject mark (after scaling if employed).

Subject Class Subject Mark
1st 100-70.0
II.1 69.9-60.0
II.2 59.9-50.0
3rd 49.9-40.0
Fail 39.9 or lower

Classing procedure

The overall Class List will be prepared by the following method. Candidates will be first placed into classes by reference to their subject classes attained, according to the lookup table shown below.  In general, the principle employed is that the candidate receives the median of their subject classes.  A second consideration is given to the arithmetic mean of the candidates’ subject rank_percentiles; candidates with an average percentile_rank of ≥ 80% will be classed in the First Class, those between 80% and 40% in the Upper Second Class and those between 40% and 20% in the Lower Second Class. Where the two methods produce different outcomes, candidates will be placed in the higher of the two resulting classes.

Candidates will be ordered into a rank order within classes by their mean percentile_ranks.

The summary of subject classes will be translated into an overall NST class by reference to the following table.

Subject classes

Overall Class

1

2.1

2.2

3

F

3

0

0

0

0

1

2

1

0

0

0

1

2

0

1

0

0

2.1

2

0

0

1

0

2.2

2

0

0

0

1

3

1

2

0

0

0

2.1

1

1

1

0

0

2.1

1

1

0

1

0

2.2

1

1

0

0

1

3

1

0

2

0

0

2.2

1

0

1

1

0

2.2

1

0

1

0

1

3

1

0

0

2

0

3

1

0

0

1

1

3

1

0

0

0

2

Fail

0

3

0

0

0

2.1

0

2

1

0

0

2.1

0

2

0

1

0

2.2

0

2

0

0

1

3

0

1

2

0

0

2.2

0

1

1

1

0

2.2

0

1

1

0

1

3

0

1

0

2

0

3

0

1

0

1

1

3

0

1

0

0

2

Fail

0

0

3

0

0

2.2

0

0

2

1

0

2.2

0

0

2

0

1

3

0

0

1

2

0

3

0

0

1

1

1

3/F

0

0

1

0

2

Fail

0

0

0

3

0

3

0

0

0

2

1

3/F

0

0

0

1

2

Fail

0

0

0

0

3

Fail

3/F:  Candidates with aggregate marks of ≥120 (40%) will be placed in the Third Class, those with less will be deemed to have failed.  Candidates who have not completed all elements of each subject may remain Unclassified.

The order-of-merit compiled by the Examiners is used as a tool to aid them in determining the overall performance of candidates. It is not meant as a firm indicator of any individual candidate's relative standing in the field.

The number of candidates in each class are included in the final markbook which is sent to Colleges.