Does the multi-authorship trend influence the quality of an article?

In the last few decades, multi-authored articles have increased in different disciplines with increasing instances of authorship abuse although multi-authorship is not always due to undeserving authorship (McDonald et al. in Mayo Clin Proc 85(10):920-927, 2010). It may be necessitated by interdisciplinary research, the evolution of a discipline, or the intention of quality improvement. This article studies the relationship between the authorship and the quality of articles (publications in better impact factor journals or core journals) in the field of Oceanography. The result shows similar to 75 % increase in the number of authors per article from 1990 to 2009 in the discipline. The increase in authorship correlates not only with the percentage of articles in core journals but also with the mean impact factor (IF) of journals (where the articles were published). The ANOVA study shows that though multi-authorship has no influence on the preference to publish in core journals during the 1990s or 2000s, it does have a significant influence on the preference to publish in high IF journals in both the decades. So these findings establish that in the field of Oceanography, the increase in collaboration would have resulted in more publications in core journals (without any influence of authorship increase) and in better impact factor journals (due to the influence of authorship increase).