This is aninformation page. It is neither anencyclopedia article nor one ofWikipedia's policies or guidelines; rather, its purpose is to explain certain aspects of Wikipedia's norms, customs, technicalities, or practices. It may reflect differing levels ofconsensus andvetting.

This passage fromWP:EXPERTSPS is often used to justify the inclusion of non-reliable/non-peer reviewed sources on the basis that they are written by experts. The most common of which being blog posts and preprints. The argument is that since these are experts, these sources become reliable. This would mean nearly all preprints are reliable sources because most preprints are written by experts.

The reality is that peer reviewed articles from experts often contain errors. Clearing peer review just means you get to be part of the scientific debate. Preprints, working papers, or other preliminary/non-peer reviewed results, contain evenmore errors because one of the goals of peer review is to find those errors. Experts make mistakes all the time, and Wikipedia should not try to get ahead of the process just because one expert, or even a team of experts, is claiming a certain discovery ahead of publication.

So when can you invoke an SPS as a reliable source? The short of it is that an SPS is acceptable for routine, non-controversial claims, but that novel claims must still, at the very least, clear the higher bar of peer-review.

Non-peer reviewed sources, such as preprints, are perfectly acceptable to sources routine, non-novel claims, such as where a certain person is employed, or some background information that is not central to the paper. For example, using the preprintarXiv:2412.10366, whose abstract reads

We could use that source to support uncontroversial statements like

• Marek Lewicki is an astrophysicist working at the University of Warsaw.<ref>arXiv:2412.10366</ref>
• Primordial black holes are a candidate fordark matter.<ref>arXiv:2412.10366</ref>

Because both are routine statements. Other sources might bepreferable, like the University of Warsaw staff website, or a book dedicated to primordial black holes, butWP:V andWP:SPS are both met.

However, we couldnot use that same source for the novel claim that

• Models that predict the same primordial black hole abundances can produce different gravitational wave spectra.<ref>arXiv:2412.10366</ref>

Why? Because that's the new result undergoing evaluation. Any sort of mistake could have happened to jeopardize that conclusion, ranging from

• Computer code mistakes, or unintentional bugs (e.g. writing 'y = mx - b' in code when 'y = mx + b' was meant)
• Flawed assumptions (e.g. assuming all the fish detected in a river are trouts when there's a mix of trout and salmon)
• Flawed statistical analysis / error analysis (e.g. thinking a result is15.5±0.5 m when it really is15.5±2.8 m)
• Modeling mistakes (e.g. assumingcows are spherical, when a cubic model would be more appropriate)

Thus if a team of experts is claiming a discovery ahead of peer-review,Wikipedia cannot say something like

Thegravitational constant,G,has been determined to be6.674305±0.000012 N⋅m²/kg².<ref>Smith, J. ... (preprint).</ref>

as if this was an established fact, or even

On July 23,a collaboration from the University of Foobarhas determined thegravitational constant,G, to a new precision of6.674305±0.000012 N⋅m²/kg², improving the accuracy by over 10 times.<ref>Smith, J. ... (preprint).</ref>

as if the determination was recognized by the scientific community.

At most, Wikipedia can say something like

On July 23,a collaboration from the University of Foobarclaims to have determined thegravitational constant,G, to a new precision of6.674305±0.000012 N⋅m²/kg², improving the accuracy by over 10 times.<ref>Smith, J. ... (preprint).</ref>

which is simply that a certain group made a certain claim, and takes no position on whether or not the claim is valid.

However, other considerations, likeWP:DUE,WP:NOTNEWS, etc., must still be met. Oftentimes, the answer is simply to wait until the claim appears in a reliable peer-reviewed venue.

Note that the above apply only topreprints, which is a term that apply to the versions of a paperprior to formal publication. It is not intended to be an authoritative resource, but rather one which is still in need of peer-review. They are usually uploaded to establish priority of discovery, but also to get feedback from the academic community, leading to an improved paper, revised arguments, correction of mistakes, etc...

A paper being on a preprint repository like arxiv is not a guarantee that it is a preprint. Several uploads are simply lecture notes, pedagogical material, or technical reports. Those are perfectly allowed underWP:EXPERTSPS.

For example

• arXiv:hep-ph/0511217 – A distilled version of a invited lecture given at theSLAC Summer Institute in 2005. This is clearly a source allowed byWP:EXPERTSPS. It is authored by an acknowleged expert in the field (only distinguished scholars are invited to give lectures), and puts no novel results forward. It summarizes the state of the field (as of 2005).
• arXiv:2101.04168 – A compilation of the first 50 issues ofJohn C. Baez'sThis Week's Finds of Mathematical Physics. These are as reliable as the original publication, authored by an acknowleged expert in the field (i.e. John C. Baez).
• arXiv:2211.07787 – A translation of a famous paper onquaternions byOlinde Rodrigues, translated byRichard Friedberg a theoretical physicist with an extensive background in mathematics. The paper was originally published inJournal de Mathématiques Pures et Appliquées, should be cited as the original source, but the translated paper can be cite alongside, for convenience to non-French speakers.

• WP:USESPS
• WP:RS
• WP:SPS
• WP:RSE
• WP:MEDRS
• WP:SCIRS
• WP:EXCEPTIONAL

• Wikipedia information pages
• Wikipedia reliable sources
• Wikipedia verifiability
• Wikipedia sources