publications - Does a preprint include revisions made in response to peer review?

This is related to but not answered in this question about the difference between various stages of a manuscript in the publication process.

After an author has submitted a manuscript to a journal for peer-review, very often the journal asks the author to revise (and resubmit) the manuscript as a precondition for its publication. I am wondering whether the term preprint refers to the manuscript before or after its authors made these revisions.

If a preprint includes revisions made in response to peer review, then there is only a slight difference, mostly regarding layout and style, between the preprint and the article that is published in the journal. From a reader’s perspective, there would be no point in paying for access to the article, since they can simply download the preprint free of charge. A publisher would probably want to prevent their authors (by publication agreements etc.) from publishing preprints that differ from the respective journal article only in form.

As a side question, what kind of preprints do publishers tolerate, as a rule?

Answer

There is no consistent terminolgoy in this respect. Sherpa/Romeo, a database for publisher’s pre-print policies and probably as close to an authority as you can get on this matter, writes about this:

The terms pre-print and post-print are used to mean different things by different people. This can cause some confusion and ambiguity.

One usage of the term pre-print is to describe the first draft of the article - before peer-review, even before any contact with a publisher. This use is common amongst academics for whom the key modification of an article is the peer-review process.

Another use of the term pre-print is for the finished article, reviewed and amended, ready and accepted for publication - but separate from the version that is type-set or formatted by the publisher. This use is more common amongst publishers, for whom the final and significant stage of modification to an article is the arrangement of the material for putting to print.

[…]

To try to clarify the situation, this listing characterises pre-prints as being the version of the paper before peer review and post-prints as being the version of the paper after peer-review, with revisions having been made.

Publisher’s policies on what authors may post on a preprint server vary a lot and Sherpa/Romeo maintains an overview over these policies. However, authors may not adhere to these policies or make the most of them when publishing their papers. Thus it is usually not possible to tell which version of the paper is published on a preprint repository.

When you want to publish your own papers, I recommend to check both, Sherpa/Romeo and the copyright agreement – most of them are suprisingly human-readable.