The reliability of Wikipedia concerns the validity, verifiability, and
veracity
Veracity may refer to:
* ''Veracity'' (album), a 2008 album by Evacuate Chicago
* Veracity (ethics), an ethical principle
* ''Veracity'' (novel), a 2010 novel by Laura Bynum
* Veracity, an automobile from the early 1900s built by the Smith Autom ...
of
Wikipedia
Wikipedia is a multilingual free online encyclopedia written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and using a wiki-based editing system. Wikipedia is the largest and most-read refer ...
and its user-generated
editing model, particularly its
English-language edition. It is written and edited by
volunteer editors who generate online content with the editorial oversight of other volunteer editors via community-generated policies and guidelines. Wikipedia carries the general disclaimer that it can be "
edited by anyone at any time" and maintains an inclusion threshold of "
verifiability, not truth". This editing model is highly concentrated, as 77% of all articles are written by
1% of its editors, a majority of whom
have chosen to remain anonymous. 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 reliability, principally regarding its content, presentation, and
editorial processes.
Studies and surveys attempting to gauge the reliability of Wikipedia have mixed results, with findings varied and inconsistent. Wikipedia's reliability was frequently criticized in the 2000s but has improved over time; it 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". 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
Selection bias is the bias introduced by the selection of individuals, groups, or data for analysis in such a way that proper randomization is not achieved, thereby failing to ensure that the sample obtained is representative of the population int ...
,
inclusion bias,
participation bias
Participation bias or non-response bias is a phenomenon in which the results of elections, studies, polls, etc. become non-representative because the participants disproportionately possess certain traits which affect the outcome. These traits me ...
, 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
Racism is the belief that groups of humans possess different behavioral traits corresponding to inherited attributes and can be divided based on the superiority of one race over another. It may also mean prejudice, discrimination, or antagonism ...
,
spin bias, corporate bias, and national bias, among others.
An
ideological bias on Wikipedia
Real or perceived ideological bias on the free online encyclopedia Wikipedia, especially on its English-language edition, has been a frequent subject of academic analysis and public criticism of the project. Questions relate to whether its cont ...
has also been identified on both conscious and subconscious levels. A series of studies from
Harvard Business School
Harvard Business School (HBS) is the graduate business school of Harvard University, a private research university in Boston, Massachusetts. It is consistently ranked among the top business schools in the world and offers a large full-time MBA p ...
in 2012 and 2014 found Wikipedia "significantly more biased" than ''
Encyclopædia Britannica
The (Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various time ...
'' but attributed the finding more to the length of the online encyclopedia as opposed to slanted editing.
The prevalence of non-neutral or conflict-of-interest editing and the use of Wikipedia for "revenge editing" has attracted publicity for inserting false, biased, or defamatory content into 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 bias
A cognitive bias is a systematic pattern of deviation from norm or rationality in judgment. Individuals create their own "subjective reality" from their perception of the input. An individual's construction of reality, not the objective input, m ...
es,
coverage discrepancies, and editor disputes. The online encyclopedia
does not guarantee the validity of its information. It is seen as a valuable "
starting point
''Starting Point'' (formerly ''Starting Point with Soledad O'Brien'') is a morning television show on CNN anchored by Soledad O'Brien. The show aired from January 2012 to June 2013. Together with the program '' Early Start'' (4.00–6.00 a.m. ...
" for researchers when they pass over content 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
Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in ...
,
toxicology
Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating expo ...
,
oncology
Oncology is a branch of medicine that deals with the study, treatment, diagnosis and prevention of cancer. A medical professional who practices oncology is an ''oncologist''. The name's etymological origin is the Greek word ὄγκος (''ó ...
,
pharmaceuticals
A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and rel ...
,
and
psychiatry
Psychiatry is the medical specialty devoted to the diagnosis, prevention, and treatment of mental disorders. These include various maladaptations related to mood, behaviour, cognition, and perceptions. See glossary of psychiatry.
Initial psych ...
were compared to professional and peer-reviewed sources in a 2005 ''
Nature
Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...
'' 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. Concerns regarding readability and the overuse of technical language were raised in studies published by the
American Society of Clinical Oncology
The American Society of Clinical Oncology (ASCO) is a professional organization representing physicians of all oncology sub-specialties who care for people with cancer. Founded in 1964 by Fred Ansfield, Harry Bisel, Herman Freckman, Arnoldus G ...
(2011), ''
Psychological Medicine
''Psychological Medicine'' is a peer-reviewed medical journal in the field of psychiatry and related aspects of psychology and basic sciences. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor of 7.723.
History ...
'' (2012),
and ''
European Journal of Gastroenterology and Hepatology'' (2014). 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 for anonymous editing; contributors are not required to provide any identification or an email address. A 2007 study at
Dartmouth College
Dartmouth College (; ) is a private research university in Hanover, New Hampshire. Established in 1769 by Eleazar Wheelock, it is one of the nine colonial colleges chartered before the American Revolution. Although founded to educate Native A ...
of 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 the ''
Ars Technica
''Ars Technica'' is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, sci ...
'' website for its methodological shortcomings.
Wikipedia trusts the same community to self-regulate and become more proficient at
quality control
Quality control (QC) is a process by which entities review the quality of all factors involved in production. ISO 9000 defines quality control as "a part of quality management focused on fulfilling quality requirements".
This approach places ...
. 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
Information technology (IT) is the use of computers to create, process, store, retrieve, and exchange all kinds of data . and information. IT forms part of information and communications technology (ICT). An information technology system (I ...
,
business
Business is the practice of making one's living or making money by producing or Trade, buying and selling Product (business), products (such as goods and Service (economics), services). It is also "any activity or enterprise entered into for pr ...
,
project management
Project management is the process of leading the work of a team to achieve all project goals within the given constraints. This information is usually described in project documentation, created at the beginning of the development process. Th ...
, knowledge acquisition,
software programming
Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming involves tasks such as anal ...
, other
collaborative
Collaboration (from Latin ''com-'' "with" + ''laborare'' "to labor", "to work") is the process of two or more people, entities or organizations working together to complete a task or achieve a goal. Collaboration is similar to cooperation. Most ...
projects and
sociology
Sociology is a social science that focuses on society, human social behavior, patterns of Interpersonal ties, social relationships, social interaction, and aspects of culture associated with everyday life. It uses various methods of Empirical ...
, 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.
Fact-checking
Fact-checking of Wikipedia is the process through which Wikipedia editors perform
fact-checking
Fact-checking is the process of verifying factual information, in order to promote the veracity and correctness of reporting.
Fact-checking can be conducted before (''ante hoc'') or after (''post hoc'') the text is published or otherwise dissem ...
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
YouTube is a global online video platform, online video sharing and social media, social media platform headquartered in San Bruno, California. It was launched on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim. It is owned by ...
and
Facebook
Facebook is an online social media and social networking service owned by American company Meta Platforms. Founded in 2004 by Mark Zuckerberg with fellow Harvard College students and roommates Eduardo Saverin, Andrew McCollum, Dustin M ...
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.
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
In commerce, a "''third-party source''" means a supplier (or service provider) who is not directly controlled by either the seller (first party) nor the customer/buyer (second party) in a business transaction. The third party is considered inde ...
as
citation
A citation is a reference to a source. More precisely, a citation is an abbreviated alphanumeric expression embedded in the body of an intellectual work that denotes an entry in the bibliographic references section of the work for the purpose of ...
s
* Verifiability of statements by respected sources
* Stability of the articles
* Susceptibility to editorial and
systemic bias
Systemic bias, also called institutional bias, and related to structural bias, is the inherent tendency of a process to support particular outcomes. The term generally refers to human systems such as institutions. Institutional bias and structur ...
* Quality of writing
Several "market-oriented" extrinsic measures demonstrate that large audiences trust Wikipedia in one way or another. For instance, "50 percent of
Sphysicians report that they've consulted ...
ikipediafor information on health conditions", according to a report from IMS Institute for Healthcare Informatics.
Comparative studies
On October 24, 2005, British newspaper ''
The Guardian
''The Guardian'' is a British daily newspaper. It was founded in 1821 as ''The Manchester Guardian'', and changed its name in 1959. Along with its sister papers ''The Observer'' and ''The Guardian Weekly'', ''The Guardian'' is part of the Gu ...
'' published a story titled "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
Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...
'' 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 (Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various time ...
''. The non-peer-reviewed study was based on ''Nature''s selection of 42 articles on scientific topics, including biographies of well-known scientists. The articles were compared for accuracy by anonymous academic reviewers, a customary practice for journal article reviews. Based on their reviews, on average the Wikipedia articles were described as containing 4 errors or omissions, while the ''Britannica'' articles contained 3. Only 4 serious errors were found in Wikipedia, and 4 in ''Britannica''. 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".
''Encyclopædia Britannica'' expressed concerns, leading ''Nature'' to release further documentation of its survey method. Based on this additional information, ''Encyclopædia Britannica'' denied the validity of the ''Nature'' study, stating that it was "fatally flawed". Among ''Britannica''s criticisms were that excerpts rather than the full texts of some of their articles were used, that some of the extracts were compilations that included articles written for the youth version, that ''Nature'' did not check the factual assertions of its reviewers, and that many points the reviewers labeled as errors were differences of editorial opinion. ''Britannica'' further stated that "While the heading proclaimed that 'Wikipedia comes close to ''Britannica'' in terms of the accuracy of its science entries,' the numbers buried deep in the body of the article said precisely the opposite: Wikipedia in fact had a third more inaccuracies than ''Britannica''. (As we demonstrate below, 's research grossly exaggerated 's inaccuracies, so we cite this figure only to point out the slanted way in which the numbers were presented.)"
''Nature'' acknowledged the compiled nature of some of the ''Britannica'' extracts, but denied that this invalidated the conclusions of the study. ''Encyclopædia Britannica'' also argued that a breakdown of the errors indicated that the mistakes in Wikipedia were more often the inclusion of incorrect facts, while the mistakes in ''Britannica'' were "errors of omission", making "''Britannica'' far more accurate than ''Wikipedia'', according to the figures".
[ ''Nature'' has since rejected the ''Britannica'' response, stating that any errors on the part of its reviewers were not biased in favor of either encyclopedia, that in some cases it used excerpts of articles from both encyclopedias, and that ''Britannica'' did not share particular concerns with ''Nature'' before publishing its "open letter" rebuttal.
The point-for-point disagreement between these two parties that addressed the compilation/text excerpting and very small sample size issues—argued to bias the outcome in favor of Wikipedia, versus a comprehensive, full article, large sample size study favoring the quality-controlled format of ''Britannica''—have been echoed in online discussions, including of articles citing the ''Nature'' study, e.g., where a "flawed study design" for manual selection of articles/article portions, the lack of study "statistical power" in its comparing 40 articles from over 100,000 ''Britannica'' and over 1 million English Wikipedia articles, and the absence of any study statistical analyses (e.g., reported ]confidence interval
In frequentist statistics, a confidence interval (CI) is a range of estimates for an unknown parameter. A confidence interval is computed at a designated ''confidence level''; the 95% confidence level is most common, but other levels, such as 9 ...
s for study results) has also been noted.
In June 2006, Roy Rosenzweig
Roy Alan Rosenzweig (August 6, 1950 – October 11, 2007) was an American historian at George Mason University in Virginia. He was the founder and director of the Center for History and New Media from 1994 until his death in October 2007 from ...
, a professor specializing in American history, published a comparison of the Wikipedia biographies of 25 Americans to the corresponding biographies found on Encarta and ''American National Biography Online''. He wrote that Wikipedia is "surprisingly accurate in reporting names, dates, and events in U.S. history" and described some of the errors as "widely held but inaccurate beliefs". However, he stated that Wikipedia often fails to distinguish important from trivial details, and does not provide the best references. He also complained about Wikipedia's lack of "persuasive analysis and interpretations, and clear and engaging prose".[ (Center for History and New Media)]
A web-based survey conducted from December 2005 to May 2006 by Larry Press, a professor of Information Systems at California State University at Dominguez Hills
California State University, Dominguez Hills (CSUDH, CSU Dominguez Hills, or Cal State Dominguez Hills) is a public university in Carson, California. It was founded in 1960 and is part of the California State University (CSU) system.
In 2020, ...
, assessed the "accuracy and completeness of Wikipedia articles". Fifty people accepted an invitation to assess an article. Of the fifty, seventy-six percent (76%) agreed or strongly agreed that the Wikipedia article was accurate, and forty-six percent (46%) agreed or strongly agreed that it was complete. Eighteen people compared the article they reviewed to the article on the same topic in the ''Encyclopædia Britannica
The (Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various time ...
''. Opinions on accuracy were almost equal between the two encyclopedias (6 favoring ''Britannica'', 7 favoring Wikipedia, 5 stating they were equal), and eleven of the eighteen (61%) found Wikipedia somewhat or substantially more complete, compared to seven of the eighteen (39%) for ''Britannica''. The survey did not attempt a random selection of the participants, and it is not clear how the participants were invited.
The German computing magazine ''c't
''c't'' – ' (''Magazine for Computer Technology'') is a German computer magazine, published by the Heinz Heise, Heinz Heise publishing house.
file:Ct jubilaeum 30 turm.jpg, The 5.71 meter high tower from the 587 published c't editions up to t ...
'' performed a comparison of '' Brockhaus Multimedial'', ''Microsoft Encarta
''Microsoft Encarta'' is a discontinued digital multimedia encyclopedia published by Microsoft from 1993 to 2009. Originally sold on CD-ROM or DVD, it was also available on the World Wide Web via an annual subscription, although later articles ...
'', and the German Wikipedia
The German Wikipedia (german: Deutschsprachige Wikipedia) is the German-language edition of Wikipedia, a free and publicly editable online encyclopedia.
Founded on March 16, 2001, it is the second-oldest Wikipedia (after the English Wikipedia), ...
in October 2004: Experts evaluated 66 articles in various fields. In overall score, Wikipedia was rated 3.6 out of 5 points (B-). A second test by ''c't'' in February 2007 used 150 search terms, of which 56 were closely evaluated, to compare four digital encyclopedias: Bertelsmann
Bertelsmann SE & Co. KGaA () is a German private multinational conglomerate corporation based in Gütersloh, North Rhine-Westphalia, Germany. It is one of the world's largest media conglomerates, and is also active in the service sector and ...
Enzyklopädie 2007, Brockhaus Multimedial premium 2007, Encarta 2007 Enzyklopädie and Wikipedia. It concluded: "We did not find more errors in the texts of the free encyclopedia than in those of its commercial competitors."
Viewing Wikipedia as fitting the economists' definition of a perfectly competitive marketplace of ideas, George Bragues (University of Guelph-Humber
The University of Guelph-Humber (UofGH) is a collaboration between the University of Guelph and Humber College.
History
The university was established in 2000 by a partnership of the University of Guelph and Humber College. The official websit ...
), examined Wikipedia's articles on seven top Western philosophers: Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
, Plato
Plato ( ; grc-gre, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy, the first institution ...
, Immanuel Kant
Immanuel Kant (, , ; 22 April 1724 – 12 February 1804) was a German philosopher and one of the central Enlightenment thinkers. Born in Königsberg, Kant's comprehensive and systematic works in epistemology, metaphysics, ethics, and ...
, René Descartes
René Descartes ( or ; ; Latinized: Renatus Cartesius; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science. Mathem ...
, Georg Wilhelm Friedrich Hegel
Georg Wilhelm Friedrich Hegel (; ; 27 August 1770 – 14 November 1831) was a German philosopher. He is one of the most important figures in German idealism and one of the founding figures of modern Western philosophy. His influence extends ...
, Thomas Aquinas
Thomas Aquinas, OP (; it, Tommaso d'Aquino, lit=Thomas of Aquino; 1225 – 7 March 1274) was an Italian Dominican friar and priest who was an influential philosopher, theologian and jurist in the tradition of scholasticism; he is known wi ...
, and John Locke
John Locke (; 29 August 1632 – 28 October 1704) was an English philosopher and physician, widely regarded as one of the most influential of Age of Enlightenment, Enlightenment thinkers and commonly known as the "father of liberalism ...
. Wikipedia's articles were compared to a consensus list of themes culled from four reference works in philosophy. Bragues found that, on average, Wikipedia's articles only covered 52% of consensus themes. No errors were found, though there were significant omissions.
''PC Pro
''PC Pro'' is one of several computer magazines published monthly in the United Kingdom by Future plc. Its headquarters is in London. ''PC Pro'' also licenses individual articles (or even the whole magazine) for republication in various countri ...
'' magazine (August 2007) asked experts to compare four articles (a small sample
Sample or samples may refer to:
Base meaning
* Sample (statistics), a subset of a population – complete data set
* Sample (signal), a digital discrete sample of a continuous analog signal
* Sample (material), a specimen or small quantity of s ...
) in their scientific fields between Wikipedia, ''Britannica'' and Encarta. In each case Wikipedia was described as "largely sound", "well handled", "performs well", "good for the bare facts" and "broadly accurate". One article had "a marked deterioration towards the end" while another had "clearer and more elegant" writing, a third was assessed as less well written but better detailed than its competitors, and a fourth was "of more benefit to the serious student than its Encarta or Britannica equivalents". No serious errors were noted in Wikipedia articles, whereas serious errors were noted in one Encarta and one ''Britannica'' article.[''PC Pro'' magazine, August 2007, p. 136, "Wikipedia Uncovered".]
In October 2007, the Australian magazine ''PC Authority'' published a feature article on the accuracy of Wikipedia. The article compared Wikipedia's content to other popular online encyclopedias, namely '' Britannica'' and Encarta
''Microsoft Encarta'' is a discontinued digital multimedia encyclopedia published by Microsoft from 1993 to 2009. Originally sold on CD-ROM or DVD, it was also available on the World Wide Web via an annual subscription, although later articles ...
. The magazine asked experts to evaluate articles pertaining to their field. A total of four articles were reviewed by three experts. Wikipedia was comparable to the other encyclopedias, topping the chemistry category.
In December 2007, German magazine ''Stern
The stern is the back or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite the bow, the foremost part of a ship. Ori ...
'' published the results of a comparison between the German Wikipedia and the online version of the 15-volume edition of ''Brockhaus Enzyklopädie
The ''Brockhaus Enzyklopädie'' (German for ''Brockhaus Encyclopedia'') is a German-language encyclopedia which until 2009 was published by the F. A. Brockhaus printing house.
The first edition originated in the '' Conversations-Lexikon'' p ...
''. The test was commissioned to a research institute (Cologne-based ''WIND GmbH''), whose analysts assessed 50 articles from each encyclopedia (covering politics, business, sports, science, culture, entertainment, geography, medicine, history and religion) on four criteria (accuracy, completeness, timeliness and clarity), and judged Wikipedia articles to be more accurate on the average (1.6 on a scale from 1 to 6 versus 2.3 for ''Brockhaus'', with 1 as the best and 6 as the worst). Wikipedia's coverage was also found to be more complete and up to date; however, ''Brockhaus'' was judged to be more clearly written, while several Wikipedia articles were criticized as being too complicated for non-experts, and many as too lengthy.
In its April 2008 issue British computing magazine ''PC Plus
''PC Plus'' was a computer magazine published monthly from 1986 until September 2012 in the UK by Future plc. The magazine was aimed at intermediate to advanced PC users, computer professionals and enthusiasts. The magazine was specifically ...
'' compared the English Wikipedia with the DVD editions of ''World Book Encyclopedia'' and ''Encyclopædia Britannica'', assessing for each the coverage of a series of random subjects. It concluded, "The quality of content is good in all three cases" and advised Wikipedia users "Be aware that erroneous edits do occur, and check anything that seems outlandish with a second source. But the vast majority of Wikipedia is filled with valuable and accurate information."
A 2008 paper in ''Reference Services Review
''Reference Services Review'' is a quarterly peer-reviewed academic journal published by Emerald Group Publishing, who acquired it from Pierian Press in 1998. The journal covers case studies and conceptual papers in all aspects of reference and us ...
'' compared nine Wikipedia entries on historical topics to their counterparts in ''Encyclopædia Britannica'', ''The Dictionary of American History'' and ''American National Biography Online''. The paper found that Wikipedia's entries had an overall accuracy rate of 80 percent, whereas the other encyclopedias had an accuracy rate of 95 to 96 percent.
A 2010 study assessed the extent to which Wikipedia pages about the history of countries conformed to the site's policy of verifiability. It found that, in contradiction of this policy, many claims in these articles were not supported by citations, and that many of those that were, sourced to popular media and government websites rather than to academic journal articles.
In April 2011, a study was published by Adam Brown of Brigham Young University
Brigham Young University (BYU, sometimes referred to colloquially as The Y) is a private research university in Provo, Utah. It was founded in 1875 by religious leader Brigham Young and is sponsored by the Church of Jesus Christ of Latter-day ...
in the journal '' PS Political Science & Politics'' which examined "thousands of Wikipedia articles about candidates, elections, and officeholders". The study found that while the information in these articles tended to be accurate, the articles examined contained many errors of omission.
A 2012 study co-authored by Shane Greenstein
Shane Greenstein is an American economist. He is the Martin Marshall Professor of Business Administration at the Harvard Business School. He is the author of two books and the co-editor of three. He has published research about Wikipedia.
Edu ...
examined a decade of Wikipedia articles on United States politics and found that the more contributors there were to a given article, the more neutral it tended to be, in line with a narrow interpretation of Linus's law
In software development, Linus's law is the assertion that "given enough eyeballs, all bugs are shallow".
The law was formulated by Eric S. Raymond in his essay and book '' The Cathedral and the Bazaar'' (1999), and was named in honor of Linu ...
.
Reavley et al. (2012) compared the quality of articles on select mental health
Mental health encompasses emotional, psychological, and social well-being, influencing cognition, perception, and behavior. It likewise determines how an individual handles stress, interpersonal relationships, and decision-making. Mental health ...
topics on Wikipedia with corresponding articles in ''Encyclopædia Britannica'' and a psychiatry textbook. They asked experts to rate article content with regard to accuracy, up-to-dateness, breadth of coverage, referencing and readability. Wikipedia scored highest on all criteria except readability, and the authors concluded that Wikipedia is as good as or better than ''Britannica'' and a standard textbook.
A 2014 perspective piece in the ''New England Journal of Medicine
''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one.
Hist ...
'' examined Wikipedia pages about 22 prescription drugs to determine if they had been updated to include the most recent FDA safety warnings. It found that 41% of these pages were updated within two weeks after the warning, 23% were updated more than two weeks later, and the remaining 36% had not been updated to include the warning as of more than 1 year later as of January 2014.
A 2014 study in the ''Journal of the American Pharmacists Association
The ''Journal of the American Pharmacists Association'' is a bimonthly peer-reviewed medical journal covering pharmacy-related topics. It was established in 1912, published as ''Journal of the American Pharmaceutical Association'' with slightly ...
'' examined 19 Wikipedia articles about herbal supplement
Herbal medicine (also herbalism) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. With worldwide research into pharmacology, some herbal medicines have been translated into modern remedies ...
s, and concluded that all of these articles contained information about their "therapeutic uses and adverse effects", but also concluded that "several lacked information on drug interactions, pregnancy, and contraindications". The study's authors therefore recommended that patients not rely solely on Wikipedia as a source for information about the herbal supplements in question.
Another study published in 2014 in '' PLOS ONE'' found that Wikipedia's information about pharmacology
Pharmacology is a branch of medicine, biology and pharmaceutical sciences concerned with drug or medication action, where a drug may be defined as any artificial, natural, or endogenous (from within the body) molecule which exerts a biochemica ...
was 99.7% accurate when compared to a pharmacology textbook, and that the completeness of such information on Wikipedia was 83.8%. The study also determined that completeness of these Wikipedia articles was lowest (68%) in the category "pharmacokinetics" and highest (91.3%) in the category "indication". The authors concluded that "Wikipedia is an accurate and comprehensive source of drug-related information for undergraduate medical education".
Expert opinion
Librarians' views
In a 2004 interview with ''The Guardian
''The Guardian'' is a British daily newspaper. It was founded in 1821 as ''The Manchester Guardian'', and changed its name in 1959. Along with its sister papers ''The Observer'' and ''The Guardian Weekly'', ''The Guardian'' is part of the Gu ...
'', self-described information specialist and Internet consultant Philip Bradley said that he would not use Wikipedia and was "not aware of a single librarian who would". He then explained that "the main problem is the lack of authority. With printed publications, the publishers have to ensure that their data are reliable, as their livelihood depends on it. But with something like this, all that goes out the window."
In 2005, the library at Trent University
Trent University is a public liberal arts university in Peterborough, Ontario, with a satellite campus in Oshawa, which serves the Regional Municipality of Durham. Trent is known for its Oxbridge college system and small class sizes. in Ontario
Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
stated Wikipedia had many articles that are "long and comprehensive", but that there is "a lot of room for misinformation and bias nda lot of variability in both the quality and depth of articles". It adds that Wikipedia has advantages and limitations, that it has "excellent coverage of technical topics" and articles are "often added quickly and, as a result, coverage of current events is quite good", comparing this to traditional sources which are unable to achieve this task. It concludes that, depending upon the need, one should think critically and assess the appropriateness of one's sources, "whether you are looking for fact or opinion, how in-depth you want to be as you explore a topic, the importance of reliability and accuracy, and the importance of timely or recent information", and adds that Wikipedia can be used in any event as a "starting point".
A 2006 review of Wikipedia by ''Library Journal
''Library Journal'' is an American trade publication for librarians. It was founded in 1876 by Melvil Dewey. It reports news about the library world, emphasizing public libraries, and offers feature articles about aspects of professional prac ...
'', using a panel of librarians, "the toughest critics of reference materials, whatever their format", asked "long standing reviewers" to evaluate three areas of Wikipedia (popular culture, current affairs, and science), and concluded: "While there are still reasons to proceed with caution when using a resource that takes pride in limited professional management, many encouraging signs suggest that (at least for now) Wikipedia may be granted the librarian's seal of approval". A reviewer who "decided to explore controversial historical and current events, hoping to find glaring abuses" said, "I was pleased by Wikipedia's objective presentation of controversial subjects" but that "as with much information floating around in cyberspace, a healthy degree of skepticism and skill at winnowing fact from opinion are required". Other reviewers noted that there is "much variation" but "good content abounds".
In 2007, Michael Gorman, former president of the American Library Association (ALA)
The American Library Association (ALA) is a nonprofit organization based in the United States that promotes libraries and library education internationally. It is the oldest and largest library association in the world, with 49,727 members a ...
stated in an ''Encyclopædia Britannica
The (Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various time ...
'' blog that "A professor who encourages the use of Wikipedia is the intellectual equivalent of a dietician who recommends a steady diet of Big Macs with everything".
''Information Today
Information Today, Inc., is an American publishing company. It publishes Internet and technology magazines, newsletters, books, directories and online products.
Information Today was previously known as Learned Information, Inc. Learned Informat ...
'' (March 2006) cites librarian Nancy O'Neill (principal librarian for Reference Services at the Santa Monica Public Library System) as saying that "there is a good deal of skepticism about Wikipedia in the library community" but that "she also admits cheerfully that Wikipedia makes a good starting place for a search. You get terminology, names, and a feel for the subject."
''PC Pro'' (August 2007) cites the head of the European and American Collection at the British Library
The British Library is the national library of the United Kingdom and is one of the largest libraries in the world. It is estimated to contain between 170 and 200 million items from many countries. As a legal deposit library, the British ...
, Stephen Bury, as stating "Wikipedia is potentially a good thing—it provides a speedier response to new events, and to new evidence on old items". The article concludes: "For ury the problem isn't so much the reliability of Wikipedia's content so much as the way in which it's used." "It's already become the first port of call for the researcher", Bury says, before noting that this is "not necessarily problematic except when they go no further". According to Bury, the trick to using Wikipedia is to understand that "just because it's in an encyclopedia (free, web or printed) doesn't mean it's true. Ask for evidence ... and contribute."
Articles on contentious issues
A 2006 article for the Canadian Library Association
The Canadian Library Association (CLA) was a national, predominantly English-language association which represented 57,000 library workers across Canada. It also spoke for the interests of the 21 million Canadians who are members of libraries. C ...
(CLA) discussed the Wikipedia approach, process and outcome in depth, commenting for example that in controversial topics, "what is most remarkable is that the two sides actually engaged each other and negotiated a version of the article that both can more or less live with". The author comments that:
Shi ''et al.'' extended this analysis in discussing "The wisdom of polarized crowds" in 2017 based on content analysis
Content analysis is the study of documents and communication artifacts, which might be texts of various formats, pictures, audio or video. Social scientists use content analysis to examine patterns in communication in a replicable and systematic ...
of all edits to English Wikipedia articles relating to politics, social issues and science from its start to December 1, 2016. This included almost 233,000 articles representing approximately 5 percent of the English Wikipedia. They wrote: "Political speech t least in the United Stateshas become markedly more polarized in recent years ... . spite early promise of the world-wide-web to democratize access to diverse information, increased media choice and social networking platforms ... reate
Rieti (; lat, Reate, Sabino: ) is a town and ''comune'' in Lazio, central Italy, with a population of 47,700. It is the administrative seat of the province of Rieti and see of the diocese of Rieti, as well as the modern capital of the Sabina re ...
echo chambers that ... degrade the quality of individual decisions, ... discount identity-incongruent opinions, stimulate and reinforce polarizing information ... foment conflict and even make communication counter-productive. Nevertheless, a large literature documents the largely positive effect that social differences can exert on the collaborative production of information, goods and services. Research demonstrates that individuals from socially distinct groups embody diverse cognitive resources and perspectives that, when cooperatively combined ... outperform those from homogeneous groups." They translated edit histories of millions of Wikipedia editors into a 7-point political identification scale and compared that with Wikipedia's six-level article quality score (stub, start, C, B, good, featured) assigned via a machine learning algorithm. They found that "articles attracting more attention tend to have more balanced engagement ... ndhigher polarization
is associated with higher quality."
Academia
Academics have also criticized Wikipedia for its perceived failure as a reliable source and because Wikipedia editors may have no expertise, competence, or credentials in the topics on which they contribute. Adrian Riskin, a mathematician in Whittier College
Whittier College (Whittier Academy (1887–1901)) is a private liberal arts college in Whittier, California. It is a Hispanic Serving Institution (HSI) and, as of fall 2022, had approximately 1,300 (undergraduate and graduate) students. It was ...
commented that while highly technical articles may be written by mathematicians for mathematicians, the more general maths topics, such as the article on polynomial
In mathematics, a polynomial is an expression consisting of indeterminates (also called variables) and coefficients, that involves only the operations of addition, subtraction, multiplication, and positive-integer powers of variables. An exa ...
s, are written in a very amateurish fashion with a number of obvious mistakes.
Because Wikipedia cannot be considered a reliable source, the use of Wikipedia is not accepted in many schools and universities in writing a formal paper, and some educational institutions have banned it as a primary source while others have limited its use to only a pointer to external sources. The criticism of not being a reliable source, however, may not only apply to Wikipedia but to encyclopedias in general—some university lecturer
Lecturer is an List of academic ranks, academic rank within many universities, though the meaning of the term varies somewhat from country to country. It generally denotes an academic expert who is hired to teach on a full- or part-time basis. T ...
s are not impressed when students cite print-based encyclopedias in assigned work. However, it seems that instructors have underestimated the use of Wikipedia in academia because of these concerns. Researchers and academics contend that while Wikipedia may not be used as a 100 percent accurate source for final papers, it is a valuable jumping off point for research that can lead to many possibilities if approached critically. What may be missing in academia is the emphasis on critical analysis
Critical thinking is the analysis of available facts, evidence, observations, and arguments to form a judgement. The subject is complex; several different definitions exist, which generally include the rational, skeptical, and unbiased analy ...
in regards to the use of Wikipedia in secondary and higher education. We should not dismiss Wikipedia entirely (there are less inaccuracies than there are errors of omission) but rather begin to support it, and teach the use of Wikipedia as an education tool in tandem with critical thinking skills that will allow students to filter the information found on the online encyclopedia and help them critically analyze their findings.
An empirical study conducted in 2006 by a Business School lecturer in Information Systems at the University of Nottingham
The University of Nottingham is a public university, public research university in Nottingham, United Kingdom. It was founded as University College Nottingham in 1881, and was granted a royal charter in 1948. The University of Nottingham belongs t ...
, the subject of a review on the technical website ''Ars Technica
''Ars Technica'' is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, sci ...
'', involving 55 academics asked to review specific Wikipedia articles that either were in their expert field (group 1) or chosen at random (group 2), concluded that: "The experts found Wikipedia's articles to be more credible than the non-experts. This suggests that the accuracy of Wikipedia is high. However, the results should not be seen as support for Wikipedia as a totally reliable resource as, according to the experts, 13 percent of the articles contain mistakes (10% of the experts reported factual errors of an unspecified degree, 3% of them reported spelling errors)."
The Gould Library at Carleton College
Carleton College ( ) is a private liberal arts college in Northfield, Minnesota. Founded in 1866, it had 2,105 undergraduate students and 269 faculty members in fall 2016. The 200-acre main campus is between Northfield and the 800-acre Cowling ...
in Minnesota
Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...
has a web page describing the use of Wikipedia in academia. It asserts that "Wikipedia is without question a valuable and informative resource", but that "there is an inherent lack of reliability and stability" to its articles, again drawing attention to similar advantages and limitations as other sources. As with other reviews, it comments that one should assess one's sources and what is desired from them, and that "Wikipedia may be an appropriate resource for some assignments, but not for others." It cited Wikipedia co-founder Jimmy Wales
Jimmy Donal Wales (born August 7, 1966), also known on Wikipedia by the pseudonym Jimbo, is an American-British Internet entrepreneur, webmaster, and former financial trader. He is a co-founder of the online non-profit encyclopedia Wikipedi ...
' view that Wikipedia may not be ideal as a source for all academic uses, and (as with other sources) suggests that at the least, one strength of Wikipedia is that it provides a good starting point for current information on a very wide range of topics.
In 2007, the ''Chronicle of Higher Education
''The Chronicle of Higher Education'' is a newspaper and website that presents news, information, and jobs for college and university faculty and student affairs professionals (staff members and administrators). A subscription is required to rea ...
'' published an article written by Cathy Davidson
Cathy N. Davidson (born 1949) is an American scholar and university professor. Beginning July 1, 2014, she is a professor at the Graduate Center of the City University of New York.
She was a professor of English at Duke University in 2006. She ...
, Professor of Interdisciplinary Studies and English at Duke University
Duke University is a private research university in Durham, North Carolina. Founded by Methodists and Quakers in the present-day city of Trinity in 1838, the school moved to Durham in 1892. In 1924, tobacco and electric power industrialist James ...
, in which she asserts that Wikipedia should be used to teach students about the concepts of reliability and credibility.
In 2008, Hamlet Isakhanli, founder and president of Khazar University
Khazar University ( az, Xəzər Universiteti, which directly translates as Caspian University) is a private university located in Baku, Azerbaijan.
Campuses
Khazar University owns four campuses in the city of Baku and two campuses in regions ...
, compared the ''Encyclopædia Britannica'' and English Wikipedia articles on Azerbaijan
Azerbaijan (, ; az, Azərbaycan ), officially the Republic of Azerbaijan, , also sometimes officially called the Azerbaijan Republic is a transcontinental country located at the boundary of Eastern Europe and Western Asia. It is a part of th ...
and related subjects. His study found that Wikipedia covered the subject much more widely, more accurately and in more detail, though with some lack of balance, and that Wikipedia was the best source for the first approximation.
In 2011, Karl Kehm, associate professor of physics at Washington College
Washington College is a private liberal arts college in Chestertown, Maryland. Maryland granted Washington College its charter in 1782. George Washington supported the founding of the college by consenting to have the "College at Chester" name ...
, said: "I do encourage y studentsto use ikipediaas one of many launch points for pursuing original source material. The best Wikipedia entries are well researched with extensive citations".
Some academic journals do refer to Wikipedia articles, but are not elevating it to the same level as traditional references. For instance, Wikipedia articles have been referenced in "enhanced perspectives" provided on-line in the journal ''Science
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Science may be as old as the human species, and some of the earliest archeological evidence for ...
''. The first of these perspectives to provide a hyperlink to Wikipedia was "A White Collar Protein Senses Blue Light", and dozens of enhanced perspectives have provided such links since then. The publisher of ''Science'' states that these enhanced perspectives "include hypernotes—which link directly to websites of other relevant information available online—beyond the standard bibliographic references".
Journalism and use of Wikipedia in the newsroom
In his 2014 book ''Virtual Unreality'', Charles Seife
Charles Seife is an American author and journalist, and a professor at New York University. He has written extensively on scientific and mathematical topics.
Career
Seife holds a mathematics degree from Princeton University (1993),Greenwood, Kath ...
, a professor of journalism at New York University
New York University (NYU) is a private research university in New York City. Chartered in 1831 by the New York State Legislature, NYU was founded by a group of New Yorkers led by then-Secretary of the Treasury Albert Gallatin.
In 1832, the ...
, noted Wikipedia's susceptibility to hoaxes and misinformation, including manipulation by commercial and political organizations "masquerading as common people" making edits to Wikipedia. In conclusion, Seife presented the following advice:
Seife observed that when false information from Wikipedia spreads to other publications, it sometimes alters truth itself. On June 28, 2012, for example, an anonymous Wikipedia contributor added the invented nickname "Millville Meteor" to the Wikipedia biography of baseball player Mike Trout
Michael Nelson Trout (born August 7, 1991) is an American professional baseball center fielder for the Los Angeles Angels of Major League Baseball (MLB). Trout is a ten-time MLB All-Star, three-time American League (AL) Most Valuable Player (MVP) ...
. A couple of weeks later, a ''Newsday
''Newsday'' is an American daily newspaper that primarily serves Nassau and Suffolk counties on Long Island, although it is also sold throughout the New York metropolitan area. The slogan of the newspaper is "Newsday, Your Eye on LI", and f ...
'' sports writer reproduced the nickname in an article, and "with that act, the fake nickname became real". Seife pointed out that while Wikipedia, by some standards, could be described as "roughly as accurate" as traditional publications, and is more up to date, "there's a difference between the kind of error one would find in Wikipedia and what one would in ''Britannica'' or ''Collier's'' or even in the now-defunct Microsoft Encarta encyclopedia ... the majority of hoaxes on Wikipedia could never have appeared in the old-fashioned encyclopedias." Dwight Garner
Dwight Garner (born January 8, 1965) is an American journalist and longtime writer and editor for ''The New York Times''. In 2008, he was named a book critic for the newspaper. He is the author of ''Garner's Quotations: A Modern Miscellany'' and ...
, reviewing Seife's book in ''The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...
'', said that he himself had "been burned enough times by bad online information", including "Wikipedia howlers", to have adopted a very sceptical mindset.
In November 2012, Brian Leveson
Sir Brian Henry Leveson (; born 22 June 1949) is a retired English judge who served as the President of the Queen's Bench Division and Head of Criminal Justice.
Leveson chaired the public inquiry into the culture, practices and ethics of the ...
was accused of having forgotten "one of the elementary rules of journalism" when he named a "Brett Straub" as one of the founders of ''The Independent
''The Independent'' is a British online newspaper. It was established in 1986 as a national morning printed paper. Nicknamed the ''Indy'', it began as a broadsheet and changed to tabloid format in 2003. The last printed edition was publis ...
'' newspaper in his report on the culture, practices and ethics of the British press. The name had been added to the Wikipedia article on ''The Independent'' over a year prior, and turned out to be that of a 25-year-old Californian, whose friend had added his name to a string of Wikipedia pages as a prank. Straub was tracked down by ''The Telegraph'' and commented, "The fact someone, especially a judge, has believed something on Wikipedia is kind of shocking. My friend went on and edited a bunch of Wikipedia pages and put my name there. ..I knew my friend had done it but I didn't know how to change them back and I thought someone would. At one point I was the creator of Coca-Cola or something. You know how easy it is to change Wikipedia. Every time he came across a red linked name he put my name in its place."
A 2016 BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
article by Ciaran McCauley similarly noted that "plenty of mischievous, made-up information has found its way" on to Wikipedia and that "many of these fake facts have fallen through the cracks and been taken as gospel by everyone from university academics to major newspapers and broadcasters."
Listing examples of journalists being embarrassed by reproducing hoaxes and other falsifications from Wikipedia in their writing, including false information propagated by major news organizations in their obituaries of
, McCauley stated: "Any journalist in any newsroom will likely get a sharp slap across the head from an editor for treating Wikipedia with anything but total skepticism (you can imagine the kicking I've taken over this article)."
''—itself banned as a source on Wikipedia in 2017 because of its perceived unreliability—has publicly stated that it "banned all its journalists from using Wikipedia as a sole source in 2014 because of its unreliability".
''
'' said in 2022 that "Screenshots of vandalized Wikipedia articles, even when reverted within minutes, often have a much longer afterlife in news reports and on social media, creating the public impression that the platform is more vulnerable to abuse than it actually is."
is the norm. While some of Wikipedia's content has passed a form of peer review, most has not.
A 2008 study examined 80 Wikipedia drug entries. The researchers found few factual errors in this set of articles, but determined that these articles were often missing important information, like
. One of the researchers noted that "If people went and used this as a sole or authoritative source without contacting a health professional...those are the types of negative impacts that can occur." The researchers also compared Wikipedia to
(MDR), by looking for answers to 80 different questions covering eight categories of drug information, including adverse drug events, dosages, and mechanism of action. They have determined that MDR provided answers to 82.5 percent of the questions, while Wikipedia could only answer 40 percent, and that answers were less likely to be complete for Wikipedia as well. None of the answers from Wikipedia were determined factually inaccurate, while they found four inaccurate answers in MDR. But the researchers found 48 errors of omission in the Wikipedia entries, compared to 14 for MDR. The lead investigator concluded: "I think that these errors of omission can be just as dangerous
, and he pointed out that drug company representatives have been caught deleting information from Wikipedia entries that make their drugs look unsafe.
A 2009 survey asked US toxicologists how accurately they rated the portrayal of health risks of chemicals in different media sources. It was based on the answers of 937 members of the
and found that these experts regarded Wikipedia's reliability in this area as far higher than that of all traditional news media:
In 2010 researchers compared information about 10 types of cancer on Wikipedia to similar data from the
's Physician Data Query and concluded "the Wiki resource had similar accuracy and depth to the professionally edited database" and that "sub-analysis comparing common to uncommon cancers demonstrated no difference between the two", but that ease of readability was an issue.
A study in 2011 came to the result that categories most frequently absent in Wikipedia's drug articles are those of drug interactions and medication use in breastfeeding.
Other categories with incomplete coverage were descriptions of off-label indications, contraindications and precautions, adverse drug events and dosing.