“24. In the Judicial Service Examination, the candidates were required to take the examination in respect of all the five subjects and the candidates did not have any option in regard to the subjects. In such a situation, moderation appears to be an ideal solution. But there are examinations which have a competitive situation where candidates have the option of selecting one or few among a variety of heterogenous subjects and the number of students taking different options also vary and it becomes necessary to prepare a common merit list in respect of such candidates. Let us assume that some candidates take Mathematics as an optional subject and some take English as the optional subject. It is well recognised that marks of 70 out of 100 in Mathematics do not mean the same thing as 70 out of 100 in English. In English 70 out of 100 may indicate an outstanding student whereas in Mathematics, 70 out of 100 may merely indicate an average student. Some optional subjects may be very easy, when compared to others, resulting in wide disparity in the marks secured by equally capable students. In such a situation, candidates who have opted for the easier subjects may steal an advantage over those who opted for difficult subjects. There is another possibility. The paper-setters in regard to some optional subjects may set questions which are comparatively easier to answer when compared to some paper-setters in other subjects who set tougher questions which are difficult to answer. This may happen when for example, in Civil Service Examination, where Physics and Chemistry are optional papers, Examiner ‘A’ sets a paper in Physics appropriate to degree level and Examiner ‘B’ sets a paper in Chemistry appropriate for matriculate level. In view of these peculiarities, there is a need to bring the assessment or valuation to a common scale so that the inter se merit of candidates who have opted for different subjects, can be ascertained. The moderation procedure referred to in the earlier para will solve only the problem of examiner variability, where the examiners are many, but valuation of answer-scripts is in respect of a single subject. Moderation is no answer where the problem is to find inter se merit across several subjects, that is, where candidates take examination in different subjects. To solve the problem of inter se merit across different subjects, statistical experts have evolved a method known as scaling, that is creation of scaled score. Scaling places the scores from different tests or test forms on to a common scale. There are different methods of statistical scoring. Standard score method, linear standard score method, normalised equipercentile method are some of the recognised methods for scaling.
