How Accurate Is Wikipedia?

When you Google the question "How accurate is Wikipedia?" the highest-ranking result is, as you might expect, a Wikipedia article on the topic ("Reliability of Wikipedia").

That page contains a comprehensive list of studies undertaken to assess the accuracy of the crowd-sourced encyclopedia since its founding 10 years ago. Of course, if you find yourself on this page, you might worry that the list itself may not be trustworthy. Well, the good news is that almost all those studies tell us that it probably is.

In 2005, the peer-reviewed journal Nature asked scientists to compare Wikipedia's scientific articles to those in Encyclopaedia Britannica—"the most scholarly of encyclopedias," according to its own Wiki page. The comparison resulted in a tie; both references contained four serious errors among the 42 articles analyzed by experts.

And last year, a study published in the Journal of Clinical Oncology found that Wikipedia had the same level of accuracy and depth in its articles about 10 types of cancer as the Physician Data Query, a professionally edited database maintained by the National Cancer Institute.

The self-described "free encyclopedia that anyone can edit" has fared similarly well in most other studies comparing its accuracy to conventional encyclopedias, including studies by The Guardian, PC Pro, Library Journal, the Canadian Library Association, and several peer-reviewed academic studies.

Still, because anyone can edit Wikipedia entries, they "can easily be undermined through malice or ignorance," noted BBC technology commentator Bill Thompson. Vandalism of Wiki entries is common in the realm of politics. In 2006, for example, slanderous comments were added to U.S. Sen. Bill Frist's biography page; the IP addresses of the computers used to make the edits traced back to some of his political rivals' staffers. To counter such activity, Wikipedia places editing restrictions on articles that are prone to vandalism.

A Small Study of Our Own

To add to the debate, Life's Little Mysteries carried out its own, albeit small, test of Wikipedia's accuracy by consulting experts from two very different walks of life: theoretical physics and pop music.

Life's Little Mysteries asked Adam Riess, professor of astronomy and physics at Johns Hopkins University and one of the scientists credited with proposing the existence of dark energy , to rate Wikipedia's "dark energy" entry.

"It's remarkably accurate," Riess said. "Certainly better than 95 percent correct."

This is not true, however, of the page about the indie pop band "Passion Pit," according to its drummer, Nate Donmoyer. Donmoyer found 10 factual errors on his band's page ranging from subtle to significant. Some information even appeared to have been added to the page by companies or organizations in search of publicity.

"It's kind of crazy," Donmoyer told LLM. "I don't think I can trust Wikipedia again. The littlest white lies can throw its whole validity off."

It may make sense that Wikipedia would have more reliable articles about academic topics than pop culture ones, considering that the latter are more prone to rumors and hearsay. On the other hand, there's no Passion Pit entry at all in Encyclopaedia Britannica. With more than three million English-language entries, Wikipedia very often wins our preference by default.

Follow Natalie Wolchover on Twitter @nattyover. Follow Life's Little Mysteries on Twitter @llmysteries, then join us on Facebook.