US scientists are significantly more likely to publish fake research than scientists from elsewhere, finds a trawl of officially withdrawn (retracted) studies, published online in the Journal of Medical Ethics.

Fraudsters are also more likely to be "repeat offenders," the study shows.

The study author searched the PubMed database for every scientific research paper that had been withdrawn -- and therefore officially expunged from the public record -- between 2000 and 2010.

A total of 788 papers had been retracted during this period. Around three quarters of these papers had been withdrawn because of a serious error (545); the rest of the retractions were attributed to fraud (data fabrication or falsification).

The highest number of retracted papers were written by US first authors (260), accounting for a third of the total. One in three of these was attributed to fraud.

The UK, India, Japan, and China each had more than 40 papers withdrawn during the decade. Asian nations, including South Korea, accounted for 30% of retractions. Of these, one in four was attributed to fraud.

The fakes were more likely to appear in leading publications with a high "impact factor." This is a measure of how often research is cited in other peer reviewed journals.

More than half (53%) of the faked research papers had been written by a first author who was a "repeat offender." This was the case in only one in five (18%) of the erroneous papers.

The average number of authors on all retracted papers was three, but some had 10 or more. Faked research papers were significantly more likely to have multiple authors.

Each first author who was a repeat fraudster had an average of six co-authors, each of whom had had another three retractions.

"The duplicity of some authors is cause for concern," comments the author. Retraction is the strongest sanction that can be applied to published research, but currently, "[it] is a very blunt instrument used for offences both gravely serious and trivial."