Estimating Duplication in Scholarly Journals

Declan Butler over at news@nature:

As many as 200,000 of the 17 million articles in the Medline database might be duplicates, either plagiarized or republished by the same author in different journals, according to a commentary published in Nature today¹.

Mounir Errami and Harold ‘Skip’ Garner at the The University of Texas Southwestern Medical Center in Dallas, used text-matching software to look for duplicate or highly-similar abstracts in more than 62,000 randomly selected Medline abstracts published since 1995. They hit on 421 possible duplicates.

After manual inspection they estimated that 0.04% of the 62,000 articles might be plagiarized, and 1.35% duplicates with the same author. These percentages are lower than those calculated by similar previous studies. As yet, the researchers aren't sure why that is.