Why a preprint's supplementary material is often the best part

Discussing preprints in this community: bring them in for early discussion, label them clearly as preprints, invite peer critique, and be prepared for the discussion to differ if the paper is later published differently.

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

This follows post #14 rather than contradicting it.

Peer review as a filter: published papers have survived a review process that rejects many submissions. Preprints have not. Neither guarantees correctness, but publication history is a difference worth noting.

I read post #16 twice before replying, because I had assumed the opposite.

How to cite a preprint: author last name, first initial, et al. Title. Server name [preprint]. Posted date. Doi. Include the server name and note that it is a preprint.

What changes between preprint and publication: authors respond to reviewer comments, re-analyse data, correct errors found in peer review, and sometimes report different results from updated analyses. The published version is not the same as the preprint.

On post #16 — agreed on the reasoning, with one qualification.

Server repositories: medRxiv for medicine, bioRxiv for biology. Preprints on these servers are time-stamped and have DOIs even if they are later published elsewhere. Citing the preprint with its DOI is appropriate while noting it is unpublished.

Unrefereed work is not worthless. A great deal of it survives review substantially unchanged. It is also the case that the version appearing in a journal frequently has different numbers, and the changes are not random — they tend to be in the direction of a smaller effect and a more careful claim.

post #21 is right about the mechanism and I think understates the practical bit.

Do not build anything on a preprint that you would mind rebuilding: if the preprint later changes substantially in revision or shows different results when published, your reasoning based on the preprint needs to be revised.

I read post #21 twice before replying, because I had assumed the opposite.

Preprints for speed: some important preliminary findings are posted as preprints to disseminate quickly. That speed is useful but comes at the cost of not yet having survived peer review. The trade-off is real.

Peer review as a filter: published papers have survived a review process that rejects many submissions. Preprints have not. Neither guarantees correctness, but publication history is a difference worth noting.

Preprints for speed: some important preliminary findings are posted as preprints to disseminate quickly. That speed is useful but comes at the cost of not yet having survived peer review. The trade-off is real.

Do not build anything on a preprint that you would mind rebuilding: if the preprint later changes substantially in revision or shows different results when published, your reasoning based on the preprint needs to be revised.

Coming back to post #25, because the follow-up matters more than the original answer.

Server repositories: medRxiv for medicine, bioRxiv for biology. Preprints on these servers are time-stamped and have DOIs even if they are later published elsewhere. Citing the preprint with its DOI is appropriate while noting it is unpublished.

Picking up post #25: that is the part I would want checked first.

I disagree with the reply above, and I think the disagreement is substantive rather than terminological.

The distinction being drawn does not survive when you look at the published data for this specific question. I would be glad to be shown wrong on this, because the version I am arguing against is more convenient.

Check whether it was later published: searching for the preprint's first author and keywords in PubMed might find a published version. The published version is the stronger citation if it exists.

Always label it as a preprint in any discussion. A preprint is not a published trial and it is not settled knowledge. Use it for hypothesis generation and for understanding emerging evidence, not for drawing definitive conclusions.