Nature took stories from Wikipedia and Britannica on 42 science-related topics and submitted them to experts for review. The experts were not told which encyclopedia the stories were from. “The exercise revealed numerous errors in both encyclopedias, but among 42 entries tested, the difference in accuracy was not great: the average science entry in Wikipedia contained around four inaccuracies; Britannica, around three,” according to Nature.

The entries covered topics including Agent Orange, quarks and synchrotrons. “Only eight serious errors, such as misinterpretations of important concepts, were detected in the pairs of articles reviewed, four from each encyclopedia … but reviewers also found many factual errors, omissions or misleading statements: 162 and 123 in Wikipedia and Britannica respectively.”

However, I stand by my earlier assertion that Wikipedia can’t provide the depth of knowledge of something like the Encyclopedia Britannica. Getting facts right is one thing, but I doubt it’s capable of providing the analysis that a professional can bring. Someone should do a similar study comparing articles about the humanities; in that case a good article would require more than just lists of facts.

Wikipedia attracted 22.3 per cent of users searching for information about the Gaza Strip as Israeli troops closed down settlements and withdrew from the region. Wikipedia’s market share numbers meant it drew five times more traffic than Google News, Yahoo News or the BBC and tied with CIA World Factbook for information on the strip.

Wikipedia tied as the second most visited site among US web users eager for details about Pope Benedict XVI, Pope John Paul II’s successor. The top destination was Newadvent.org, the old-school Catholic encyclopedia that has resisted the temptation to go Wikipedia-style.

But the way it does things now, Wikipedia will never be the last place to learn about a subject (as might a traditional encyclopedia, such as the Encyclopedia Britannica). Yes, when someone introduces flagrant errors into an article, it’s usually corrected in minutes. But minor factual errors or common misunderstandings sometimes go uncaught.

More importantly, Wikipedia lacks the judgment of expertise. It’s not that experts are always right. But they have the status to offer assessments that others don’t, and we can trust their judgments to a degree–they usually begin with the benefit of the doubt. Wikipedia’s anonymous contributors can’t claim the same status. They can cite references and offer facts to bolster their interpretations, but in order to verify their correctness, someone must learn enough about the subject to offer a critique–i.e. she must become an expert herself. Then the value of the encyclopedia becomes questionable.

I rank Wikipedia about where I put friends’ opinions–good enough to explain ordinary matters and to point me in the right direction but not worth risking anything over.