Nature asked a team of experts to review 42 entries and were not told which encyclopaedia the information came from.
The researchers found eight serious mistakes - four in each encyclopaedia. There were many more minor errors, including omissions and misleading statements: 162 in Wikipedia and 123 in Brittanica.
Researchers did criticise some Wikipedia entries for being poorly structured. But the results will not be good news for Brittanica which has faced increasing pressure from free, easily-updated, web-based resources.
More news from journalism.co.uk:
Clash of the titans: old vs new media
Wikipedia prankster confesses to false posting
Journalism stalwart condemns 'flawed' Wikipedia
Switching on to democratic citizen media
The darker side of citizen journalism
Wikinews supercharged by London bombings coverage
Wikinews trumpets online revolution
Free daily newsletter
- WikiTribune announces launch editor and plans to publish first edition this year
- Johann Hari to return to Independent in '4 or 5 weeks'
- Johann Hari offers to repay Orwell Prize money
- Orwell Prize delays 'unanimous' Johann Hari decision
- CMS 2010: Newspapers wasting money on expensive columnists, says Jimmy Wales