Wikipedia:Reliable source examples

This is an essay.

It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints.

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WP:RSE

This page provides examples of what editors on Wikipedia have assessed to be a reliable source. The advice is not, and cannot be, comprehensive, and should be used primarily to inform discussion in an article talk page with respect to sources. Exceptions can naturally be made using common sense, in order to reach a collaborative conclusion. Advice can be sought on the talk page of this essay.

You can discuss reliability of specific sources at Wikipedia:Reliable sources/Noticeboard.

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Advice by subject area

Physical sciences and medicine

Science article in the popular press

Articles in newspapers and popular magazines generally lack the context to judge experimental results. They may emphasize the most extreme possible outcomes mentioned in a research project and gloss over caveats and uncertainties, for instance presenting a new experimental medicine as the "discovery of the cure" of a disease. Also, newspapers and magazines sometimes publish articles about scientific results before those results have been peer-reviewed or reproduced by other experimenters. They also tend not to report details of the methodology that was used, or the degree of experimental error. Thus, popular newspaper and magazine sources are generally not the best sources for scientific and medical results, especially in comparison to the academic literature.

What can a popular-press article on scientific research provide? The mainstream press is valuable for reporting the public perception of scientific topics and for summarizing their implications for public policy. Such articles can also be used as pointers to more substantive information on the science itself. For instance, a newspaper article quoting Joe Smith of the Woods Hole Oceanographic Institution regarding whales' response to sonar gives you a strong suggestion of where to go to find more: look up his work on the subject, and cite his published papers instead of the newspaper article.

arXiv preprints and conference abstracts

arXiv is the oldest and most popular e-print server for scientific publications. arXiv is owned by Cornell University and funded, in part, by the National Science Foundation. Although arXiv papers do not necessarily undergo peer review prior to publication, arXiv exercises several mechanisms of editorial control. Publishing at arXiv requires authors to obtain endorsements for the topic areas in which they publish. This ensures that authors have an appropriate background and that the paper is appropriate for the topic area. Papers which appear unscholarly are removed from arXiv. Papers which are inappropriate for a subject area are removed or reclassified. In general arXiv is more selective than other open-access sites such as philica.com.

Publication at arXiv does not necessarily ensure the same level of quality as publication venues which require prior peer review. Researchers may publish on arXiv for different reasons: to establish priority in a competitive field, to make available newly developed methods to the scientific community while the publication is undergoing peer-review, and sometimes to bypass peer review (perhaps because the paper is of questionable quality, perhaps because the author thinks publishing at arXiv is adequate).

A number of questions should be considered when considering the reliability of an arXiv e-print:

1. Has the paper been accepted for publication in a peer reviewed journal?

2. Has the paper been cited in peer reviewed journals by other papers?

3. What are the qualifications of the paper’s authors? Do the authors possess degrees in relevant fields? Have they published peer reviewed papers in the field? Do their institutional affiliations lend confidence to their work?

4. Does the e-print itself cite papers showing consistent results? Confidence in an e-print is significantly enhanced if a number of peer reviewed articles are in agreement with its findings.

5. Has the article been subjected to post-publication peer review at a scholarly venue for that purpose such as www.naboj.com or JournalReview.org?

There are a growing number of sources on the web that publish e-prints of articles and conference abstracts. Websites exercise various levels of editorial control. Unless the source exercises editorial control, e-prints and conference abstracts should be considered to be self-published. The above questions can be used to consider the reliability of self-published scientific material. See the policy on self-published sources at WP:SPS. Many of them are also primary sources, which should be treated with caution. See the policy advice on primary sources.

Evaluating experiments and studies

There are techniques that scientists use to prevent common errors, and to help others replicate results. Some characteristics to look for are experimental controls (such as placebo controls or heretofore best-treatment controls) and double-blind assignment of treatments to experimental units (e.g. patients for medical studies); additionally triple-blind measurement of outcomes improves quality.

Reliable studies don't just present conclusions. Details about the design and implementation of the experiment should be available. Summary measurements should be available. Unless privacy concerns prohibit their disclosure, raw data should be made available in a supplementary report or by request.

Law

There are several legal structures for the creation, validation and enforcement of law and the resulting corpus of law is only valid in the jurisdiction of origin. The opinion of experts within the jurisdiction is therefore preferred, in general, to that of outside commentators. Legal material may also be divided into the legal statement itself, material to support or inform that legal statement and judgments of opinion when applying the law in practice.

When discussing legal texts, it is more reliable to quote from the text, or from appropriately qualified jurists or textbooks than from newspaper reporting. Some nations allow public-domain copying of administration documents, such as in Italy, so large sections can be quoted (without copyright restrictions) or primary texts could be copied to Wikisource.

Business and commerce

Material published by a trading organisation is a view of how that organisation looks on itself however it will also have a marketing component and may lack neutrality. If this material is used it should carry a caveat to indicate this risk and should be corroborated with independent reporting if possible. The accounts and notes to the accounts for all publicly listed companies are required to have been independently audited and will contain a statement to that effect, possibly with caveats considered significant by the auditors. Smaller companies and partnerships which are not publicly listed may have audited accounts. These accounts should provide a reliable view as to the financial health of the organisation however this is subject to the accounting principles applied, which should be identified in the notes. Due to the specialised skills required to assess financial health this material should not be used in isolation, a more acceptable judgement of the organisation can be obtained from investment analysis conducted in some segments of the business press, stock markets and significant investment vehicles. It should be noted that in some cases these assessments may be confidential.

Any judgements in Wikipedia with regard to trading organisations should be explicitly referenced and caveated with comments as to the reliability and range of sources used.

Crime statistics

Crime statistics may detail crime reported to the police, crime recorded by the police (crime reports may not be recorded at the discretion of police), or crime experienced by the public – whether reported or not (determined by survey). Different police departments will have different rules for how to categorise and whether to record crime. This varies from country to country.

Where multiple crimes are committed in a single event, it is common to record only the most serious offense. In some countries, Police department districts may differ from municipal boundaries. Police crime recording rules are often revised leading to a problem in comparing crime rates from one year to another.

As a result, use of summarised crime statistics from raw data to indicate the criminality of a certain area in comparison with others or the prevalence of a certain type of crime constitutes original research. Editors should use reliable secondary sources for commentary on trends in the criminality or peacefulness of a district.

Popular culture and fiction

Articles related to popular culture and fiction must be backed up by reliable sources like all other articles. However, due to the subject matter, many may not be discussed in the same academic contexts as science, law, philosophy and so on; it is common that plot analysis and criticism, for instance, may only be found in what would otherwise be considered unreliable sources. Personal websites, wikis, and posts on bulletin boards, Usenet and blogs should still not be used as secondary sources. When a substantial body of material is available, the best material available is acceptable, especially when comments on its reliability are included.

Religious sources

In significant world religious denominations with organized academies or recognized theological experts in religious doctrine and scholarship, the proceedings of official religious bodies and the journals or publications of recognized and well-regarded religious academies and experts can be considered reliable sources for religious doctrine and views where such views represent significant viewpoints on an article subject. Ordination alone does not generally ensure religious expertise or reliability. Absent evidence of stature or a reputation for expertise in a leading, important religious denomination or community, the view of an individual minister or theologian is ordinarily not reliable for representing religious views.

Secondary sources are not necessarily from recent years – or even centuries. The sacred or original text(s) of the religion will always be primary sources, but any other acceptable source may be a secondary source in some articles. For example, the works of Thomas Aquinas are secondary sources for a Roman Catholic perspective on many topics, but are primary sources for Thomas Aquinas or Summa Theologica.