Confused about writing sample

[Kink]

Does the writing sample necessarily need to be a graded paper?

[Strangefox]

Does the writing sample necessarily need to be a graded paper?

No. It can be also an article, published or unpublished. The most important thing - it must be a sample of ACADEMIC writing.

[fuzzylogician]

It doesn't have to be graded (unless specifically required by a school), but I'd strongly recommend that you submit a paper that has been reviewed and commented on by your professors--as opposed to a new paper that no one has had the chance to read. It has to be academic, as strangefox says, and it should preferably be in the (sub)field for which you are applying, if possible.