I used to work at Britannica, so I’m not just shooting from the cuff here. The fact is that most articles in the Encyclopedia aren’t written by experts. They’re written by the staff of editors, whose responsibility it is to do some basic research into a topic before writing the article. Now, ideally those editors would be trained in the topic they specialize in, but sometimes that’s not the case. I knew a science editor there who had been an English major in college. The major articles, though — the ones over 1,000 words — were commissioned for area experts (professors, scientists, etc.) and are more reliable. Most likely this 12 year old was looking at shorter pieces that were composed by someone who was doing his or her best, but who relied on bad or vague source material. I’ve been there and done that — quite literally.

That being said, the advantage of Britannica is it does have a staff of people who believe in what they do and work hard to get things right. It’s their job to consult source materials, phone experts, and rigorously fact-check their materials. They’re paid to get it right, which is why it’s notable — and worthy of newspaper articles and cheap shots from bloggers — when they don’t. Wikipedia is a useful resource, but it’s susceptible to a series of its own potential failings, some of which Britannica avoids by — get this — paying professionals to do their job.