Researchers found in a 2017 study that edits to Wikipedia about scientific subjects influenced the content of scientific literature and what studies would be cited in papers based on their usage on the “online encyclopedia.” Last year, another study found edits about Spanish cities had a measurable impact on tourist activity and an earlier study found investor sentiment could also be influenced. In the case of scientific research, the results showed that the creation of one Wikipedia page influenced up to 250 scientific papers.

While there are no apparent studies on the online encyclopedia’s political impact, research has found a left-wing bias on the site. Breitbart previously reported news articles and academic works copied the biased Wikipedia article on GamerGate, an anti-corruption movement against left-wing journalists and activists in the video game community.

The 2017 study titled “Science Is Shaped by Wikipedia: Evidence From a Randomized Control Trial” was conducted by MIT research scientist Neil Thompson and University of Pittsburgh economics professor Douglas Hanley. In order to test the influence of Wikipedia on scientific literature, the researchers commissioned students to create and publish articles on chemistry topics not covered on the site. A control group of topics had pages created about them, but not published.

Chemistry journals were then checked in the ensuing months to determine how similar papers on the respective groups of topics were to each other. Thompson and Hanley’s experiment showed the coverage in scientific journals of topics with existing Wikipedia articles had greater similarity than their coverage of topics without articles. They attributed some part of this similarity in coverage to Wikipedia due to the rate of common-word matches with the site. Extrapolating from their findings, the researchers concluded each article created as part of their experiment had influenced as many as 250 scientific papers.

Further analysis determined how Wikipedia articles impacted the number of citations studies received. Using a random selection of citations from both published and unpublished pages in their experiment, the researchers found citations in public Wikipedia pages saw an approximate 91 percent increase in citations in the scientific literature, suggesting authors of scientific papers used the online encyclopedia to gather sources. Thompson and Hanley note this could reflect researchers using Wikipedia as a source, but citing the study due to the controversy of using the online encyclopedia. Such findings rebut prior research disputing any citation impact from Wikipedia.

Economic impact has also been researched. Last year, a study by European researchers found Wikipedia can influence tourism. The study involved expanding articles about cities in Spain and comparing the impact with cities whose articles were not expanded. Researchers, using publicly-released monthly statistics about hotel stays, found adding just two paragraphs increased hotel stays by 9 percent and if the city had a particularly short article, the increase could be as much as 33 percent. A Chinese study from 2013 found the more content added about a company on Wikipedia the more restrained negative investor sentiment became.

Researchers involved in these studies tended to view Wikipedia’s influence as a positive and evidence the site should be relied on more. However, other research found the site has a political bias. Shane Greenstein and Feng Zhu in a Harvard paper concluded Wikipedia showed bias towards left-wing views and was more biased than the expert-written Encyclopedia Britannica. German researchers in 2018 studying the editing of articles on German politicians by individuals from the German parliament noted edits seemed to be focused on elections and suggested experimenting to determine the effect of such editing.

Breitbart’s own reporting has shown how edits on Wikipedia influence the outside coverage of contentious political subjects. At the end of last year Breitbart News reported dozens of news outlets and academic works copied material from Wikipedia about the GamerGate anti-corruption movement in gaming. Wikipedia’s article on GamerGate has long been dominated by left-wing activists opposed to the movement, which criticized corrupt gaming journalists in progressive outlets. The copying from Wikipedia included whole paragraphs being copied uncredited in academic text books and even outlets such as the BBC copying extensively from Wikipedia.

Political bias on the site has also affected press outlets such as The Gateway Pundit, which has several times been smeared in the press by reports apparently deriving information from Wikipedia, in one case also affecting a Berkman Klein study. Gateway Pundit is one of numerous conservative news outlets, including The Epoch Times and Breitbart itself, that have been banned from use as sources by Wikipedia’s left-wing community.

Wikipedia’s proven influence on economic, political, and academic, matters makes it an attractive target for partisan activists (including some associated with political campaigns), paid editors, and hoaxers. Despite this, journalists and Big Tech continue to push the narrative of Wikipedia as a vital tool in combatting the “fake news” threat on the Internet and integrate it into their services or model them after the online encyclopedia’s system.

T. D. Adler edited Wikipedia as The Devil’s Advocate. He was banned after privately reporting conflict of interest editing by one of the site’s administrators. Due to previous witch-hunts led by mainstream Wikipedians against their critics, Adler writes under an alias.