The proportion of the top papers that appear in elite journals has fallen since the late 1980s and early 1990s, according to a new study by researchers from Canada and Estonia.
In a paper submitted on 24 April 2013 to the preprint repository ArXiv, Vincent Lariviere of Université de Montréal, George A. Lozano of Estonian Centre of Evolutionary Ecology and Yves Gingras of Université du Québec à Montréal, examined the citation patterns over the past 40 years of seven traditionally-elite journals and six that have been increasing in importance over the past 20 years.
The “elite” journals chosen were Nature, Science, Proceedings of the National Academy of Science (PNAS), Cell, Lancet, New England Journal of Medicine (NEJM), and the Journal of the American Medical Association (JAMA).
The “emerging” journals chosen, which were amongst those that had the highest growth in their proportion of top-cited papers over the past 40 years, were: PLoS One, Nano Letters, Advanced Materials, Nature Materials, Journal of Clinical Oncology and Chemical Reviews.
The researchers used Thomson Reuters’ Web of Science from 1970 to 2010 (1970-2012 for citations received). They studied a fixed citation window of the two-years following publication and used two citation thresholds: the top 5 per cent most cited papers and the top 1 per cent most cited.
Analysis of the two groups of titles revealed that all the elite journals now publish a smaller proportion of the top-cited papers than they did 20 to 25 years ago. For example, the authors of the study found that, in the mid-1980s, PNAS published almost 9 per cent of the top 1 per cent most cited papers, and over 4 per cent of the top 5 per cent most cited papers. These percentages in 2010 were about 2.7 per cent and 2.2 per cent respectively. Similarly, in the late 1980s and early 1990s Nature and Science published respectively about 7 per cent and 6 per cent of the top 1 per cent most cited papers. These percentages are now about 4 per cent and 3 per cent, according to the research.
In contrast, the research indicated that the proportion of top papers published in “emerging” journals has increased. PLoS One, for example, according to the study currently accounts for 0.6 per cent of the top 1 per cent most-cited papers and 0.8 per cent of the top 5 per cent most-cited papers. Two other journals defined as "emerging" in the study, Nature Materials and Nano Letters, currently have over 0.5 per cent and 1 per cent of the top 1 per cent most-cited papers, respectively.
The authors note that, ‘since the late 1980s and early 1990s, several new and some long-established journals are becoming more important, while traditional elite journals, including Science and Nature, are publishing a decreasing proportion of the top-cited papers. However, even though their share of the most cited articles is declining, elite journals still “punch above their weight” and publish a larger proportion of top cited papers than we might expect from their total number of papers.’
The authors attribute the shift in emphasis away from “elite” journals to a range of factors, many due to the effects of the internet. Firstly, they note, ‘the digital age made papers more independent of their respective journals … papers are now directly accessible independently and one does not have to even look at the corresponding issue or volume of the journal. Hence, whether papers get cited or ignored is increasingly independent of the journal in which they appear.’
Secondly, they observe that the internet has made it easier to create new journals because digital journals are easier and cheaper to produce and distribute than print-based journals – and this can take market share from existing titles.
A third trend that they identify is the issue of access. Some “emerging” journals that are picking up a greater share of top papers are open access. According to the authors, ‘Researchers now access papers from a greater variety of journals, not just the so-called premier journals in a given field, or elite journals in general. Technically, a paper could now be in any journal, and it would still be found by internet searches, downloaded if available, and cited if deemed relevant.’
In addition, the authors suggest that the high rejection rates of “elite” journals might be a deterrent to researchers in choosing where to submit their papers. They write: ‘researchers might prefer to save time and submit their papers to other journals that ultimately will reach the same audience faster and potentially obtain as many citations. In the digital age it is relatively easy to determine the actual citation rate of individual papers or authors, so the value of a journal’s reputation is now less important.’
The authors urge advancement, recruitment and grant-evaluation committees, administrators and other evaluators to take note of their analysis. They write: ‘The quality of papers and competence of researchers should be evaluated independently of the journal in which the work appeared for two reasons… Although there shall always be a hierarchy of journal prestige, the hierarchy is dynamic. Many other, more suitable criteria can be used to assess researchers, but if journal quality must be used, equity demands that evaluators become attentive to changes in the scientific publishing landscape.’