Poor correlation of the Journal Impact Factor with scientific impact

Wed, 13 Mar 2019 00:00:00 +0000

Definition of the Journal Impact FactorThe Journal Impact Factor (JIF or short IF) of Journal X is the number of citations found from all journals & proceedings (in the Web of Science core collection ) published in 2017 to articles in Journal X, divided by the number of articles that were published in the two previous years (2016 and 2016). For the JIF, only journals and proceedings count (not books) and within journals only original articles and reviews (editorials, letters and meeting abstracts do not count).As one can easily see, there are several factors in this description that lend themselves to interpretation and manipulation by humans. First, any writing in a scientific journal needs to be classified (e.g. whether it is an article or a letter) and that classification is made by humans. Furthermore, the selection of what is included in the Web of Science core collection is not a fixed constant, but the list is updated dynamically by humans.Web of Science versus ScopusSo what about journals that are not in the WoS core collection? I have published e.g. an article in a German-language journal ( Lymphologie in Forschung und Praxis ). This Journal is not included in any WoS collection. Despite initial reservations, this review article has meanwhile gathered 8 citations, which is a remarkable success given that the median citation count of a scientific publication is four ( source ; see also this blog post ). How can I report the JIF when some grant application requires me to list it?Luckily, there is still competition to the Impact Factor, namely the Cite Score . That number was invented by the World’s largest scientific publisher Elsevier . Elsevier keeps also count of citations in the Scopus database. Scopus is less choosy when it comes to journal selection and most journals that are not listed in the WoS core collection are listed by Scopus.**ResearchGate Journal Impact?**So what do you do if your journal is not listed by either of the two big scientometric providers? There is still one other metric that you can use, namely ResearchGate . The RG Journal Impact is not well documented (at least I could not find much) but presumably uses a similar method. However, it is difficult to trust a metric if you do not know how it is calculated. I have published exactly one article that is not counted by WoS or Scopus. However, this is due to fact that the journal ( Frontiers in Biotechnology and Bioengineering ) is young. Its publisher has announced that it will receive an impact factor still this year and that the Impact Factor will be quite nice. For the time being, I am using the RG Journal Impact ( 3.02 ).Large discrepancies in the journal evaluationEven though the way the cite score is calculated is very similar to the JIF, the resulting numbers can be surprisingly different. At the bottom of this text is a comparison of the JIF, Cite Score and RG Journal Impact for three different journals from the year 2015, in which I have published. One notable difference is that the JIF takes into consideration the 2 previous years, whereas the Cite Score considers the previous 3 years. However, that does not explain the majority of the differences. The Cite Score is also less choosy when it comes to the content type: it counts - unlike the JIF - also editorials and letters (as a rule of thumb it counts everything).A weak correlationThe Impact factor is misused. It was developed to evaluate journals (for librarians to decide whether to subscribe to a journal or not) and has then subsequently been used to evaluate individual articles and even individual researchers. The correlation between the Impact Factor and the actual scientific impact (e.g. measured in terms of citations) has been steadily declining over the last decades (see e.g. this research: https://arxiv.org/abs/1205.4328) . From my personal experience, I can confirm that this is true as the correlation between the JIF and the actual number of citation among my own publications is around 0.32. This is pretty bad if your goal is to use the JIF as a proxy to predict scientific impact in terms of future citations.UPDATEThe 2018 Impact Factor for Frontiers in Biotechnology and Bioengineering is 5.122 ( https://www.frontiersin.org/journals/bioengineering-and-biotechnology# ). Congratulations!

Being indexed

Tue, 03 Nov 2015 00:00:00 +0000

There are many databases storing and analysing scientific publications . “Being indexed” or “being listed” simply means for a journal that one of these databases includes the articles that are published in this journal. Importantly, several of these databases also include citation data for each article; therefore they are often referred to as journal citation databases. Since there are many such databases, virtually every journal is “listed” somewhere and if you want to get your journal listed, there are several guides out there, e.g. Getting your journal indexed . However, in the life sciences, there are a few databases that are substantially more important and authoritative than others. The big three are MEDLINE , Web of Science and Scopus . How are these three databases different? Clearly, the most important journals are covered by all of them. But less important journals and journals that publish in non-English languages might be only listed by one or two of the three. The databases have different journal selection criteria (see below) and the selection is subject to constant change.MEDLINE MEDLINE is a non-commercial database that is maintained by the US-American National Library of Medicine and the selection of journals happens under NIH -oversight. MEDLINE and especially its online portal PubMed are exceptional due to their free accessibility for everybody. In fact, PubMed is probably the only transparent academic bibliographic database that can be used for free by everybody to research life science literature. MEDLINE currently indexes 5620 journals.Web of ScienceThe Web of Science comprises several databases and they used to be maintained by the Institute of Scientific Information (ISI), before it was sold to Thomson Scientific & Healthcare (nowadays Thomson Reuters ). The ISI was founded by Eugene Garfield , who is considered to be the father of bibliometrics and scientometrics . The Web of Science currently indexes 13762 journals (combined Arts & Humanities, Expanded Science and Social Sciences Citation Indexes).ScopusThe other commercial journal database is Scopus , which is owned by Elsevier , the largest publisher of scientific journals. Scopus is the largest of these three databases covering many more journals than the other two. According to some, this is due to the somewhat loosely applied journal selection criteria ( http://www.issi2015.org/files/downloads/all-papers/1198.pdf) . There has also been some discussion about the independence of the journal selection for commercial databases. After all, according to a study published in PlosOne, five companies control more than half of all academic publishing, with Elsevier dominating at about 25% of the market ( http://dx.doi.org/10.1371/journal.pone.0127502) . Scopus indexes currently over 22000 journals.People have been comparing databases and citation counts (e.g. here ). One database, that I have been omitting is Google Scholar . Even though the free accessibility of Google Scholar and its broader approach to measure impact have advantages as opposed to Web of Science or Scopus, Google Scholar is - similar to the general Google search engine - not very open about what journals and sources its search covers. In my opinion, this is a big draw-back, but on the other hand Google probably constantly has to tweak its algorithm to avoid exploitation. If you want to know more about Google Scholar as a citation database, I recommend this article . Journal ListsMEDLINE: ftp://ftp.nlm.nih.gov/online/journals/lsi2015.xml,http://www.ncbi.nlm.nih.gov/nlmcatalog?cmd=historysearch&querykey=1 (currently indexed)http://www.ncbi.nlm.nih.gov/nlmcatalog/?term=reportedmedline (all)Web of Science/Thomson Reuters: http://ip-science.thomsonreuters.com/mjl/Scopus : https://www.elsevier.com/__data/assets/excel_doc/0015/91122/title_list.xlsx Journal selection criteriaMEDLINE: https://www.nlm.nih.gov/pubs/factsheets/jsel.htmlWeb of Science/Thomson Reuters: http://wokinfo.com/essays/journal-selection-process/Scopus : https://www.elsevier.com/__data/assets/pdf_file/0006/95118/SC_FAQ-content-selection-process-22092014.pdf

Scopus on Michael’s Domain

Poor correlation of the Journal Impact Factor with scientific impact

Being indexed