Question

When you write a research paper, why should you never choose a topic on which you're already

an expert?

Answer 1

You shouldn't choose a topic that you're already an expert on for several reasons. First off, you aren't learning anything. The whole point of a research paper is to learn something new.

Secondly, you could gloss over facts. If you already know a lot about a topic, it's easy to assume that the person reading your work knows the same amount as you, but that isn't always true, so it might not make sense to them and they might not understand

Answer 2

If you were to write a paper on a subject you have already mastered, you are not learning anything new and thus defeating part of the purpose for a research paper. The point of writing a research paper is so that you may research and learn about a new topic, which may help to serve you in the future. Writing about a topic you already know may also become repetitive and not interesting to those who you may present your research to.