There's a silent war being waged on Wikipedia. Entries on so-called "controversial" scientific topics are persistently edited to reflect ideology, not facts.

While topics like evolution, alternative medicine, climate change, and nuclear power are not scientifically controversial, they are politically controversial. It is for this reason that those topics often fall victim to "edit wars" on Wikipedia, where users alter information to fit their biased beliefs or tarnish the integrity of the page with slanderous statements. Other users respond by correcting the changes.

Adam Wilson and Gene Likens, both based out of the University of Connecticut, were curious just how often this happens. So they downloaded the complete revision histories (dating from 2003 to 2012) of three politically controversial scientific topics -- acid rain, global warming, and evolution -- and compared them to four politically uncontroversial topics -- heliocentrism, general relativity, continental drift, and the standard model in physics. They found that significantly more edits were made to the controversial topics compared to the uncontroversial ones, and far more words were changed per day on average.

For the authors, the study was personal. As experts in acid rain, and frequent visitors to the acid rain entry on Wikipedia, they noticed myriad attempts to "introduce balderdash and factual errors" to the page's content. Particularly memorable was a series of edits which began on November 30, 2011:

At 10:20am, an anonymous editor (identified only by an IP address), removed the introductory paragraph which defined acid rain and replaced it with a statement calling acid rain “a load of bullshit.” This change was quickly reverted, but the next day the paragraph was again deleted and replaced by “Acid rain is a popular term referring to the deposition of wet poo and cats.” Five minutes later this edit was reverted and repeated again, and then reverted again. The following day (December 2, 2011) another sentence was changed from “During the 1990s, research continued.” to “During the 1990s, research on elfs continued,” which remained for over seven hours. Later that day the sentence "AciD Rain [sic] killed bugs bunny” was briefly added. Fifteen minutes later the section title “Chemistry in cloud droplets” was changed to “Blowjobs.”

Wikipedia now has numerous algorithms meant to prevent such obvious cases of vandalism, but some subtle, yet nefarious, edits evade detection.

"For example, less than a month later, the sentences, 'Acid rain does not directly affect human health. The acid in the rainwater is too dilute to have direct adverse effects' were briefly changed to 'Acid rain directly affect [sic] human health. The acid in the water is too concentrated to have indirect adverse effects,'” Wilson and Likens wrote.

Wilson and Likens' study makes an elucidating point, but it does suffer from a few drawbacks. For example, the duo did not analyze the edits themselves to determine if they were valid or invalid. Moreover, it's possible that the increase in edits on controversial topics could simply result from the fact that they are viewed more often. Lastly, the authors neglected to examine edits to Wikipedia pages on vaccines and GMOs, which are certainly the controversies du jour.

Wikipedia is the sixth most visited website in the world. Hundreds of millions look to the encyclopedia for fact-based knowledge. Compromised pages can easily spread misinformation.

To prevent misinformation getting loose, Wilson and Liken offered some advice.

"Users should be aware that content in Wikipedia can be extremely dynamic; two students could obtain, within seconds, diametrically different information on a controversial scientific topic. Educators should ensure that students understand the limitations and appropriate uses of Wikipedia, especially for controversial scientific issues."

Update 8/17: Juliet Barbara of the Wikimedia Foundation has responded to the paper:

"[T]he study simply seems to confirm that the articles chosen as controversial are, in fact, controversial. Although the authors reference anecdotal examples of inaccuracies, they note that it is, in fact, “difficult to assess causality.”"

She adds:

"Wikipedia has been widely found to be as accurate as traditional sources including Encyclopedia Britannica and the German-language encyclopedia Brockhaus. Automated accounts or “bots” detect and revert vandalism within seconds. Volunteer editors and administrators regularly ensure content meets the site’s policies and guidelines. Vandalism and inaccuracies occur, but thanks to Wikipedia’s open, collaborative model the vast majority of inaccurate content is removed within minutes."

Source: Wilson AM, Likens GE (2015) Content Volatility of Scientific Topics in Wikipedia: A Cautionary Tale. PLoS ONE 10(8): e0134454. doi:10.1371/journal.pone.0134454

(Image: AP)