A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

State your reasons
Moving from a topic to a question to a working hypothesis
Part I. Research and writing: from planning to production

Put at the top of separate pages each reason that might support your best hypothesis, even if you have only one or two (for more on reasons, see 5.4.2). Imagine explaining your project to a friend. You say, I want to show that Alamo stories helped develop a unique Texan identity, and your friend asks, Why do you think so? Your reasons are the general statements that you offer to support your answer: Well, first, the stories distorted facts to emphasize what became central to Texan identity; second, the stories were first used to show that Texas (and the Wild West) was a new kind of frontier; third, . . . and so on.

If you can think of only one or two reasons (you'll usually need more), put placeholders at the tops of pages: Reason 3: Something about Alamo stories making Texans feel special. If you know only how you want a reason to support your answer, state that: Reason 4: Something to show that Alamo stories were more than just myth. Each reason, of course, needs support, so for each reason, ask Why do I think that? What evidence will I need to prove it? That will help you focus your search for evidence (see 2.3.3 and 5.4.2).

If you're new to your topic or early in your project, your reasons may be only educated guesses that you'll change; if you don't, you might not be self-critical enough. But a list of reasons, no matter how speculative, is the best framework to guide your research and focus your thinking, and certainly better than no reasons at all.