Edited sentence: After examinations of 42 pairs, Nature obtain the following results :.Britanica : 123 errors, so an average of 2,92 by article.In early december 2005, the scientist review Nature publied  the result of a comparative experience between Britannica and the english Wikipedia.It appear than Britanica stay of a better quality than its concurrent, but not so much, which can confirm the " de facto " concurrence between Britannica and the new alternative Wikipedia.Scientists didn't know the source.This first serious comparative experience propose to scientists expert in their topics 2 articles about a same subject, one from Britanica, one from Wikipedia (.Wikipédia : 162 errors, so an average of 3,86 by article.« Researchers should read Wikipedia cautiously and amend it enthusiastically