Finally, researchers Taha Yasseri, Anselm Spoerri, Mark Graham and János Kertész have done the hard work of measuring which Wikipedia controversies provoke the most heated fights. Their summary of what people around the world can’t agree on is somewhat heartening, because a surprising amount of the disagreement is actually just about soccer.

Five of the 10 most controversial pages in the Spanish language Wikipedia are about football clubs, F.C. Universitatea Craiova is the most controversial page in the Romanian language Wikipedia, and Beitar Jerusalem F.C. also makes the list in Hebrew. Those debates seem more manageable than arguments over the Hungarian far right, former Chilean autocrat Augusto Pinochet, and Jesus, each the subject of multiple persistent controversies, or George W. Bush, anarchism, and Muhammad, the three most controversial pages in English.

Indeed, if you’re worried about our society’s ability to reach agreement on what to do about climate change, you should take comfort in the fact that at least in the English-language Wikipedia, the article on global warming is not as controversial as the list of World Wrestling Entertainment personnel.

“There are differences between different cultures and different languages,” said Spoerri, an information scientist at Rutgers University and an author of the paper, which will be published as a chapter in a book on Wikipedia next year. “If you look at Spanish, the controversies are more about sports than about politics and geography.” The most controversial page in the German Wikipedia, he added, is the article on Croatia, which is a site for verbal spats between Croats and Serbs who speak German. For a full discussion, read lead author Yasseri’s post on the group’s research.

The researchers measured controversy by counting the number of times one editor made a change to a line in an article that another editor then canceled, reverting the text to its previous state. They weighted this number to rule out opportunistic vandals and multiplied it by the number of readers involved in editing the article to create an index of controversiality. The result is a culturally neutral measurement that can be used to compare disputes around the world. The chart below shows overlaps in this index among the French, German, Spanish and English Wikipedias. Articles on Jesus and homeopathy are in dispute in all four languages, while articles on anarchism, socialism, global warming and Mexico are controversial in at least three of the four.

This chart shows controversial topics in the English, Spanish, German, and French Wikipedias. More controversial topics are closer to the center.
This chart shows controversial topics in the English, Spanish, German and French Wikipedias. More controversial topics are closer to the center.

After watching Spoerri’s tutorial, you can play with the visualization tool yourself.

The results are particularly fascinating in the context of a paper that another group led by Yasseri published last year on how Wikipedia controversies develop over time. In almost all cases, the editors working on a Wikipedia page eventually reach a consensus, and the index of controversiality stops increasing. The chart below shows this trend in an article on the cartoons of Mohammad that the Danish newspaper Jyllands-Posten published in 2005. The researchers compared controversy to a “consumable resource,” like a mineral -- something that is eventually exhausted.

In rare cases, however, the debate is never exhausted. Here is the same graph drawn for articles on President Obama (in black) and anarchism (in red). There is no indication from the graphs that either of these trends are weakening. The disputes are not tending toward a consensus.

Among the 3.2 million articles Yasseri’s group studied last year, fewer than 100 appeared to be on a definite trajectory toward perpetual disagreement. That’s an excellent record for Wikipedia. Insofar as the free encyclopedia provides a model for intellectual collaboration through social media, those results are also encouraging for the pursuit of knowledge in general.

Still, there will be some controversies that just can’t be resolved, ones that involve unanswerable religious questions, for example, or deeply felt national or regional loyalties.

“These you can easily understand where the disagreement is, and there can be points of view that see the world very differently,” Spoerri said of the most controversial topics. “It’s not about what’s true or about what’s right or wrong.”

In these cases, he argued, Wikipedia at least provides users with a transparent and inclusive forum for debate, even if it is too much to hope for a conclusive version of the history of F.C. Universitatea Craiova.