The role of assumptions is to simplify a problem, so we can solve it faster – sometimes so we can solve it, period. You are very likely to do this for a research paper, and you'll have to present them up front because they affect everything else you write. Assumptions are a sign that we don't know everything, and we want to move forward based on what we do know. For instance, in a business plan you estimate how much your company is worth now (in which case your assumptions explain where the value comes from) and how much you will make, say, in your first year of business (your assumptions say where the sales are coming from)
The best assumptions are either true or they don't kill you (i.e. leave your audience mocking your stupidity). The worst assumptions are the ones you use again and again until you use them automatically (i.e. assumptions about political opponents, who must be wrong because, well, they're opponents, see?). In the business world, bad assumptions lead to lost customers, lost opportunities, complaints, legal problems, negative social media campaigns and mocking YouTube videos.
How to make assumptions
- understand what is and is not physically or humanly possible (e.g. you can't turn invisible or teleport, etc. so don't make assumptions that call on others to do those things)
- understand that what's worked well in the past does not have to work well here and now
- understand clearly how other options may cost too much, take too long, break laws or strain relationships
- recognize that your view may not be OK with everyone, and seek out other views if you can
- be ready for and open to new information that can change your resulting actions (e.g. something you ignored that really can't be ignored)
Once you have them in place, you have to write them down, which gives readers the freedom to disagree and even scoff. This is better by a long shot than making the assumptions, telling nobody, and finding they're wrong later complete with the public exposure (and maybe even legal problems) that comes. (This is an excellent reason to have others review your work before you hand it in.) Hint: readers are most likely to scoff if
- something's missing among your assumptions (“a miracle occurs”)
- something is wrong and they know it (especially if it's illegal, immoral or something will break)
- you run out of money, people or supplies before the job is done
On the other hand, if they don't disagree with your assumptions, you'll find they are likely to go along with everything you have to say.
If the readers don't get what you're saying, the assumptions won't matter one way or another. But assuming you can write clearly, you can help the readers out by
- listing all the assumptions together
- repeating each one (and any definitions) as you have to refer to it
Bottom line: you'll do it anyway. So do it right, do it completely, review it and write it all down!