Nature Investigates Britannica and Wikipedia
The journal Nature publishes a news item comparing Encyclopedia Britannica with Wikipedia and finds them close in accuracy. Of the examined science articles, Britannica’s content averaged about 3 errors per article. Wikipedia’s averaged about 4. The study doesn’t sound very scientific: it’s a very small sample of content on both of the encyclopedia’s Web sites.
"As well as comparing the two encyclopaedias, Nature surveyed more than 1,000 Nature authors and found that although more than 70% had heard of Wikipedia and 17% of those consulted it on a weekly basis, less than 10% help to update it. The steady trickle of scientists who have contributed to articles describe the experience as rewarding, if occasionally frustrating (see ‘Challenges of being a Wikipedian‘)."