Web of Science and Scopus: Understanding the indexing system
- 1. UNDERSTANDING THE INDEXING SYSTEM OF THE JOURNALS A) Web of Science (WoS) 1. The Science Citation Index (SCI) is a highly selective subset of journals found in the Science Citation Index Expanded. Journals in SCI are typically the most consistently high impact titles in many scientific disciplines. The Science Citation Index (SCI) was officially launched in 1964. It is now owned by Clarivate Analytics (previously Thomson Reuters). The Science Citation Index (SCI) is a sub-set of the Science Citation Index Expanded (SCIE), containing journals that rank competitively among the most highly-cited core journals in their category or categories. 2. The Science Citation Index Expanded (SCIE) is a larger version that covers more than 8,500 notable and significant journals, across 150 disciplines, from 1900 to the present. These are the world's leading journals of science and technology, because of a rigorous selection process. Thomson Reuters, journals of Science Citation Index (SCI), and Science Citation Index Expanded (SCIE) have the same quality as the journal selection process for journals of SCI and SCIE is essentially identical. The small difference between Science Citation Index® (SCI) and Science Citation Index ExpandedTM (SCIE) is the storage format. As known, both SCI and SCIE are available online. However, SCI is available on CD/DVD format but SCIE is not. 3. The Emerging Source Citation Index (ESCI) is a less rigorous citation index produced since 2015 by Thomson Reuters (Currently Clarivate Analytics). ESCI includes "peer- reviewed publications of regional importance and in emerging scientific fields. It is one of the core databases of Web of Science but the easiest to get through. SCI and SCIE are affiliated to the Journal citation report (JCR) which calculates the Impact Factor as a quality tool (Criticized for journal quality instead of the quality of individual scientific article). ESCI is not affiliated with JCR, which simply means the journal will not have any impact factors. All the articles in ESCI databases will go individual review by the scientific committee of WoS and the selected article will be archived in the core collection. 4. Art and Humanities Citation Index covers the entire major scientific and social sciences related journal. B) Scopus 1. Scopus is Elsevier’s abstract and citation database similar to the WoS by Clarivate Analytics. Scopus covers top-level journals in life sciences, social sciences, physical sciences, and health sciences. All journals covered in the Scopus database are reviewed each year to ensure high- quality standards in scientific research. 5. The SCImago Journal & Country Rank (SJCR) is a publicly available portal that includes the journals and country scientific indicators developed from the information contained in the Scopus® database (Elsevier B.V.). These indicators can be used to assess, analyze and compare Journals. Country rankings may also be compared or analyzed separately. UNDERSTANDING IMPACT INDEXES There are several tools which enable users to look up and automatically calculate the impact indicators of the most important scientific journals: Journal Citation Reports (JCR):
- 2. It includes publications reviewed by the most widely-cited experts in the world and covers approximately 200 different disciplines. JCR can be accessed online via the Web of Science platform (WOS) and can be used to run online searches and look up the Impact Factor of a given journal or a group of journals and make comparisons between these. The impact factor is calculated annually by the Institute for Scientific Information (ISI). An impact factor is an essential tool for investigating the level of influence and impact that a journal has had on the international research community rather than of an article. It is updated every year and may vary from one year to another. Impact factor calculation in the journal citation report (JCR): Impact Factor (IF): The total number of citations in the previous two years / total number of articles published in those previous two years SCIMAGO Journal and Country Rank (SJR): This ranking emerged as a free-of-charge alternative to JCR. It analyses publications indexed in the Scopus database which is provided by the publisher Elsevier. SJR does not measure the quality of an article but rather the quality of the journal in which the article is published. It may vary every year as IF. It enables to see journal quality based on the citation which can be used to compare the quality of the journal. One single journal can be associated with several subject areas and it is very likely that the jour SJR includes a greater number of journals than the JCR, making it less selective. Impact index calculation by SJR: The SJR citation period is three years - one year longer than JCR - and it can be calculated on a yearly basis from 1999, although data from Scopus publications have been compiled since 1996. In addition to this, the calculation disregards citations to documents published within the journal itself. Quartiles: In addition to the Impact Factor or Impact Index, rankings of journals in each subject category are divided into quartiles by both JCR and SJR. These quartiles rank the journals from highest to lowest based on their impact factor or impact index. There are four quartiles: Q1, Q2, Q3, and Q4. Journals occupy Q1 in the top 25% group Journals occupy Q2 in the 25 to 75% group Journals occupy Q3 in the 50 to 75% group Journals occupy Q4 in the 75 to 100% group. The most prestigious journals within a subject area are those occupying the first quartile, Q1. The importance of the other journals declines as we move down through the quartiles.