The reliability of Wikipedia and its volunteer-driven and community-regulated editing model, particularly its English-language edition, has been questioned and tested. Wikipedia is written and edited by volunteer editors (known as Wikipedians) who generate online content with the editorial oversight of other volunteer editors via community-generated policies and guidelines. The reliability of the project has been tested statistically through comparative review, analysis of the historical patterns, and strengths and weaknesses inherent in its editing process. The online encyclopedia has been criticized for its factual unreliability, principally regarding its content, presentation, and editorial processes. Studies and surveys attempting to gauge the reliability of Wikipedia have mixed results. Wikipedia's reliability was frequently criticized in the 2000s but has been improved; its English-language edition has been generally praised in the late 2010s and early 2020s.
Select assessments of its reliability have examined how quickly vandalism—content perceived by editors to constitute false or misleading information—is removed. Two years after the project was started, in 2003, an IBM study found that "vandalism is usually repaired extremely quickly—so quickly that most users will never see its effects".Fernanda B. Viégas, Martin Wattenberg, Kushal Dave: Studying Cooperation and Conflict between Authors with history flow Visualizations . Proceedings of the SIGCHI conference on Human factors in computing systems, 575–582, Vienna 2004, The inclusion of false or fabricated content has, at times, lasted for years on Wikipedia due to its volunteer editorship. Its editing model facilitates multiple systemic biases, namely selection bias, inclusion bias, participation bias, and group-think bias. The majority of the encyclopedia is written by male editors, leading to a gender bias in coverage, and the make up of the editing community has prompted concerns about racial bias, spin bias, corporate bias, and national bias, among others. An ideological bias on Wikipedia has also been identified on both conscious and subconscious levels. A series of studies from Harvard Business School in 2012 and 2014 found Wikipedia "significantly more biased" than Encyclopædia Britannica but attributed the finding more to the length of the online encyclopedia as opposed to slanted editing.
Instances of non-neutral or conflict-of-interest editing and the use of Wikipedia for "revenge editing" has attracted attention to false, biased, or defamatory content in articles, especially biographies of living people. Articles on less technical subjects, such as the social sciences, humanities, and culture, have been known to deal with misinformation cycles, cognitive biases, coverage discrepancies, and editor disputes. The online encyclopedia does not guarantee the validity of its information. Nevertheless, it is regarded as a valuable "starting point" for researchers seeking to examine the listed references, citations, and sources. Academics suggest reviewing reliable sources when assessing the quality of articles.
Its coverage of medical and scientific articles such as pathology, toxicology, oncology, pharmaceuticals, and psychiatry were compared to professional and peer-reviewed sources in a 2005 Nature study. The study (which was not in itself peer-reviewed) was cited in many news articles such as this: A year later Encyclopædia Britannica disputed the Nature study, whose authors, in turn, replied with a further rebuttal.Fatally Flawed: Refuting the recent study on encyclopedic accuracy by the journal Nature. Encyclopædia Britannica, March 2006 Concerns regarding readability and the overuse of technical language were raised in studies published by the American Society of Clinical Oncology (2011), Psychological Medicine (2012), and European Journal of Gastroenterology and Hepatology (2014). The Simple English Wikipedia serves as a simplified version of articles to make complex articles more accessible to the layperson on a given topic in Basic English. Wikipedia's popularity, mass readership, and free accessibility has led the encyclopedia to command a substantial second-hand cognitive authority across the world.
Wikipedia editing model Wikipedia allows anonymous editing; contributors (known as "editors") are not required to provide any identification or an email address. A 2009 study of Dartmouth College in the English Wikipedia noted that, contrary to usual social expectations, anonymous editors were some of Wikipedia's most productive contributors of valid content. The Dartmouth study was criticized by John Timmer of Ars Technica for its methodological shortcomings.
Wikipedia trusts the same community to self-regulate and become more proficient at quality control. Wikipedia has harnessed the work of millions of people to produce the world's largest knowledge-based site along with software to support it, resulting in more than nineteen million articles written, across more than 280 different language versions, in fewer than twelve years. For this reason, there has been considerable interest in the project both academically and from diverse fields such as information technology, business, project management, knowledge acquisition, software programming, other collaborative projects and sociology, to explore whether the Wikipedia model can produce quality results, what collaboration in this way can reveal about people and whether the scale of involvement can overcome the obstacles of individual limitations and poor editorship which would otherwise arise.
Wikipedia's degree of truthfulness extends from its technology, policies, and editor culture. Edit histories are publicly visible. Footnotes show the origins of claims. Editors remove unverifiable claims and overrule ("revert") claims not phrased in a neutral point of view (NPOV). Wikipedia editors also tend towards self-examination and acknowledge Wikipedia's flaws. Its open model permits article-tampering (vandalism) including short-lived jokes and longer hoaxes. Some editors spend much time trolling (creating vandalism, spam, and harassment), while others spend much time improving the encyclopedia, however, trolling is quickly reverted. The English Wikipedia's editor pool, roughly 40,000 active editors who make five edits monthly, largely skews male and white, leading to gender- and race-based systemic biases in coverage. Variations in coverage mean that Wikipedia can be both, as online communities professor Amy S. Bruckman put it, "the most accurate form of information ever created by humans" on the whole while short articles can be "total garbage".
Academics view Wikipedia as representing a "consensus truth" in which readers can check reality in an age of contested facts. For example, when facts surrounding the COVID-19 pandemic rapidly changed or were debated, editors removed claims that did not adhere to the "verifiability" and "NPOV" guidelines.
Fact-checking
Fact-checking of Wikipedia is the process through which Wikipedia editors perform fact-checking of content published in Wikipedia, while fact-checking using Wikipedia is the use of Wikipedia for fact-checking other publications. The broader topic of fact checking in the context of Wikipedia also includes the cultural discussion of the place of Wikipedia in fact-checking. Major platforms including YouTube and Facebook use Wikipedia's content to confirm the accuracy of information in their own media collections. Seeking public trust is a major part of Wikipedia's publication philosophy.
Wikipedia has grown beyond a simple encyclopedia to become what The New York Times called a "factual netting that holds the digital world together". Common questions asked of search engines are answered using knowledge ingested from Wikipedia, and often credit or link to Wikipedia as their source. Wikipedia is likely the most important single source used to train generative artificial intelligence (AI) models, such as ChatGPT, for which Wikipedia is valued as a well-curated data set with highly structured formatting.: "While estimates of its influence can vary, Wikipedia is probably the most important single source in the training of A.I. models. ... In fact, no one I spoke with in the tech community seemed to know if it would even be possible to build a good A.I. model without Wikipedia." The accuracy of AI models depends on the quality of their training data, but these models are also fundamentally unable to cite their original source for their knowledge; thus AI users use Wikipedia knowledge without knowing that Wikipedia is its source. AI users also receive results that intertwine facts originating from Wikipedia with fictional data points (AI hallucinations), lowering the quality of information absent a real-time fact-check during information retrieval.
Assessments
Criteria for evaluating reliability The reliability of Wikipedia articles can be measured by the following criteria: Accuracy of information provided within articles Appropriateness of the images provided with the article Appropriateness of the style and focus of the articles Susceptibility to, and exclusion and removal of, false information Comprehensiveness, scope and coverage within articles and in the range of articles Identification of reputable third-party sources as citations Verifiability of statements by respected sources Stability of the articles Susceptibility to editorial and systemic bias Quality of writing
Several "market-oriented" extrinsic measures demonstrate that large audiences trust Wikipedia in one way or another. For instance, "50 percent of [US] physicians report that they've consulted ... [Wikipedia] for information on health conditions", according to a report from IMS Institute for Healthcare Informatics.
Comparative studies
On October 24, 2005, the British newspaper, The Guardian, published a story entitled "Can you trust Wikipedia?" in which a panel of experts were asked to review seven entries related to their fields, giving each article reviewed a number designation from 0 to 10. Most of these reviewed articles received marks between 5 and 8. The most common critiques were poor prose, or ease-of-reading issues (three mentions), omissions or inaccuracies, often small but including key omissions in some articles (three mentions), and poor balance, with less important areas being given more attention and vice versa (one mention). The most common praises were factually sound and correct, no glaring inaccuracies (four mentions), and much useful information, including well-selected links, making it possible to "access much information quickly" (three mentions).
In December 2005, the journal Nature published results of an attempted blind study seeking reviewer evaluations of the accuracy of a small subset of articles from Wikipedia and Encyclopædia Britannica. The non-peer-reviewed study was based on Natures selection of 42 articles on scientific topics, including biographies of well-known scientists. Factual errors, omissions or misleading statements found in the sampled articles was 162 for Wikipedia and 123 for Britannica (4:3). For serious errors, such as misinterpretations of important concepts, 4 were found in Wikipedia, and 4 in Britannica (1:1). The study concluded that "Wikipedia comes close to Britannica in terms of the accuracy of its science entries", although Wikipedia's articles were often "poorly structured".