A preprint whose numbers changed substantially at publication

This follows the opening post rather than contradicting it.

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.

I read post #7 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.

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.

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.

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.

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.

post #67 is right about the mechanism and I think understates the practical bit.

Thank you for the correction. I have edited my earlier post with a note rather than silently, so the thread still makes sense to read. The error was mine and it was the kind that comes from remembering a figure instead of looking it up.

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.

I read post #81 twice before replying, because I had assumed the opposite.

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.