To examine whether National Institutes of Health (NIH) funded articles that were archived in PubMed Central (PMC) after the release of the 2008 NIH Public Access Policy show greater scholarly impact than comparable articles not archived in PMC.
A list of journals across several subject areas was developed from which to collect article citation data. Citation information and cited reference counts of the articles published in 2006 and 2009 from 122 journals were obtained from the Scopus database. The articles were separated into categories of NIH funded, non-NIH funded and whether they were deposited in PubMed Central. An analysis of citation data across a five-year timespan was performed on this set of articles.
A total of 45,716 articles were examined, including 7,960 with NIH-funding. An analysis of the number of times these articles were cited found that NIH-funded 2006 articles in PMC were not cited significantly more than NIH-funded non-PMC articles. However, 2009 NIH funded articles in PMC were cited 26% more than 2009 NIH funded articles not in PMC, 5 years after publication. This result is highly significant even after controlling for journal (as a proxy of article quality and topic).
Our analysis suggests that factors occurring between 2006 and 2009 produced a subsequent boost in scholarly impact of PubMed Central. The 2008 Public Access Policy is likely to be one such factor, but others may have contributed as well (e.g., growing size and visibility of PMC, increasing availability of full-text linkouts from PubMed, and indexing of PMC articles by Google Scholar).
URL : Examining the Impact of the National Institutes of Health Public Access Policy on the Citation Rates of Journal Articles
DOI : 10.1371/journal.pone.0139951
The aim of this paper is to extend our knowledge about the power-law relationship between citation-based performance and collaboration patterns for papers of the Natural Sciences domain. We analyzed 829,924 articles that received 16,490,346 citations. The number of articles published through collaboration account for 89%. The citation-based performance and collaboration patterns exhibit a power-law correlation with a scaling exponent of 1.20, SD=0.07. We found that the Matthew effect is stronger for collaborated papers than for single-authored.
This means that the citations to a field research areas articles increase 2.30 times each time it doubles the number of collaborative papers. The scaling exponent for the power-law relationship for single-authored papers was 0.85, SD=0.11. The citations to a field research area single-authored articles increase 1.89 times each time the research area doubles the number of non-collaborative papers.
URL : http://arxiv.org/abs/1510.05266
A statistical analysis of full text downloads of articles in Elseviers ScienceDirect covering all disciplines reveals large differences in download frequencies, their skewness, and their correlation with Scopus-based citation counts, between disciplines, journals, and document types. Download counts tend to be two orders of magnitude higher and less skewedly distributed than citations. A mathematical model based on the sum of two exponentials does not adequately capture monthly download counts.
The degree of correlation at the article level within a journal is similar to that at the journal level in the discipline covered by that journal, suggesting that the differences between journals are to a large extent discipline specific. Despite the fact that in all study journals download and citation counts per article positively correlate, little overlap may exist between the set of articles appearing in the top of the citation distribution and that with the most frequently downloaded ones.
Usage and citation leaks, bulk downloading, differences between reader and author populations in a subject field, the type of document or its content, differences in obsolescence patterns between downloads and citations, different functions of reading and citing in the research process, all provide possible explanations of differences between download and citation distributions.
URL : http://arxiv.org/abs/1510.05129
Do highly productive researchers have significantly higher probability to produce top cited papers? Or does the increased productivity in science only result in a sea of irrelevant papers as a perverse effect of competition and the increased use of indicators for research evaluation and accountability focus? We use a Swedish author disambiguated data set consisting of 48,000 researchers and their WoS-publications during the period of 2008 2011 with citations until 2014 to investigate the relation between productivity and production of highly cited papers. As the analysis shows, quantity does make a difference.
URL : http://arxiv.org/abs/1510.01871
« There are scientific and educational institutions in Ukraine which actively introduce and fill up open sources in web to make integration of Ukrainian scientists into worldwide communication more effective. Ukrainian scientists’ citation boost with their complete works available at open sources must indicate the success of such integration. This article, grounding in Scopus and Google Scholar data, investigates the types of scientific web-sources used by Ukrainian scientists for promotion of their works. »
URL : http://eprints.rclis.org/25210/
30 mai 2015
· 18 h 34 min