What would make a bad research topic and why?

Answer 1

I do not know what level of research topic you are asking about. A good research topic for a grade school course might be a bad research topic for a graduate course. Nor do you identify the type of research. A research topic for a science course would not make a good research topic for a history course and vice versa. Now having said that here are a few criteria.
1) Topic must be well defined and have limited potential answers.
2) Topic should be relevant to the course for which the research is done.
3) The topic must be one around which you can frame a thesis statement.
4) The topic must be one for which there is a potential answer.
5) The answer(s) to the question must have some relevance or interest. Ask your self "Why would someone care about this topic.
6) Adequate resources must be available to complete your research. You will need to do a literature review.

Answer 2

A topic where you can't find any evidence, research or testimony for it....