UPSC Mains Exam 2025: How to choose a right Optional Subject — 5 key factors to consider

Indian Express

5 hours ago

A student, an MBBS doctor from a reputed medical college in the country, inquired about the best optional subject for an upcoming UPSC CSE attempt. During the discussion, a suggestion was made – 'With a background in medical sciences, why not choose the same subject as the optional?' The student responded that medical science is a lengthy optional subject and requires more time to cover than average humanities subjects like sociology or anthropology.
This exchange raises questions about the continued relevance of the optional subject in the UPSC Examination Scheme. It is for this reason that many states have eliminated the optional subject component from their respective state examinations.
Nonetheless, since the optional subject is still a part of the UPSC exam cycle, it is important to understand the factors an aspirant should consider while selecting one. It is worth noting that the optional subject carries a weightage of 500 marks out of the total 1750 marks in the Mains stage—amounting to 28.5% of the total. Any decision regarding the optional subject is critical and can either secure a top 10 rank or significantly impact one's chances of selection.
There are a total of 48 optional subjects available, from which a candidate must select one. Of these, 25 are core academic subjects, and 23 are literature-based.
Some of the factors that should be kept in mind while selecting the optional subject are:
If your bachelor's/master's subject is there in the list of the 48 optional subjects of UPSC, the first preference should be given to that subject. The very fact that you've invested 3-5 years in that subject makes that subject a natural choice. Your mind has adapted to the needs of the subject, and you can save a lot of time because you need not read the entire subject from scratch. Also, while choosing an optional subject, a degree of risk management should be involved. An optional subject is a subject that you would be required to read for 1-4 years, if need be, if you appear for multiple attempts. Hence, choosing a subject that's more convenient and comfortable to you would help to tackle it more efficiently and for longer durations. This criterion should command the heaviest weight while selecting the optional subject for UPSC.
There is a lot of debate on social media regarding the 'trending optional subject'. During the era of 1990s, Public Administration used to be the favourite subject, then came History, and currently PSIR, Sociology, and Anthropology are the most sought-after subjects.
As per the UPSC Annual Report 2022-2023:
In optional subjects, the marks awarded by the examiner are not final. If the chief examiner believes that the marking has been too liberal compared to other optional subjects, they have the authority to reduce the scores. This process of moderation is followed by the UPSC, unlike the scaling method adopted by State Public Service Commissions (PSCs).
There is no fixed scheme for moderation, and it varies from year to year. Many myths surrounding this moderation circulate on social media, often pressuring students into choosing specific optional subjects. However, due to a lack of information and transparency, no official moderation criteria are available online. Therefore, this factor should not influence an aspirant's decision when selecting an optional subject.
Several subjects—such as PSIR, Geography, History, and Sociology—have considerable overlap with the General Studies (GS) papers. While this overlap can be a helpful consideration, it should only carry limited weight. It should not be the sole criterion for selecting an optional subject.
To illustrate this point, consider a hypothetical scenario:
Suppose a candidate chooses Geography as the optional subject solely due to its overlap with the GS syllabus, despite not having a strong interest in it. Geography contributes, on average, 90–120 marks to GS Paper I. In attempting to gain these 90–120 marks, the candidate risks the entire 500 marks allocated to the optional papers—merely on the basis of this overlap.
Hence, it is never advisable to compromise the 500 marks of the optional papers just to gain a few additional marks in the GS papers. Overlap should be considered the least important criterion when selecting an optional subject. Think of the optional as a multi-year commitment that can become mentally exhausting if not chosen wisely.
The length of the syllabus varies across optional subjects. Subjects like Mathematics and History have more extensive syllabi, while others like Sociology and Anthropology are comparatively shorter and can typically be completed within 4 to 4.5 months. For working aspirants, the syllabus length can be a significant factor in decision-making.
An interesting data point from the UPSC Annual Report 2022–2023 reveals that while 60.4% of selected candidates in UPSC 2022 were from engineering backgrounds, 80.8% chose humanities-based optional subjects. This implies that a majority of engineering students do not opt for subjects like Physics, Chemistry, or Mathematics as their optional, instead preferring humanities subjects for their more concise syllabi.
Additionally, if a candidate does not select their graduation or post-graduation subject as their optional and chooses a completely new subject, they must consider the availability of teachers and study materials. It is advisable to avoid subjects that lack sufficient academic resources or where qualified guidance is not readily accessible.
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