What is SCI and the impact factor?
The Science Citation Index (now the Science Citation Index Expanded, or SCIE) is one of the core databases included in the products Web of Knowledge and Web of Science, owned by Thomson Reuters (http://ipscience.thomsonreuters.com/product/web-of-science/).
In fact, Web of Science comprises a number of database resources, and the journals covered are subject to an evaluation process before inclusion.
Publishers wishing to get their journals evaluated need to submit a proposal to a committee which oversees the Web of Science Core Collection Journal Selection Process.
The evaluation takes into consideration a number of criteria, and it is notable that these include not just analysis of the citations to its content, but also factors such as the editorial process and adherence to good publishing practices (e.g. in relation to the peer review process and timeliness of publication) and also the scope and international provenance of the journal.
The following link contains more information about the criteria:
www.wokinfo.com/essays/journal-selection-process/ (accessed 4 May 2016).
This shows why a journal will expect you to follow certain processes and adhere to deadlines during the submission process, and also to format your article to meet their formatting criteria. They make these stipulations so that they themselves can adhere to the standards required by the selection and inclusion process.
Statistics from Thomson Reuters show that about 3500 journals are evaluated annually, and around 10% will be selected for inclusion. Once included, the ‘citation impact’ is published annually in the summer detailing the Journal Impact Factor of those journals included.
The first ‘impact factors’ were published in 1975.
Impact factors are published in an annual report known as the Journal Citation Reports (JCR), which is part of the Web of Science portfolio.
You need to have a subscription to access the Web of Science content and reports, but many institutions will have this. Talk to your librarian or departmental colleagues if you are unsure if you have access or how to use the products.
What is an ‘impact factor’
The impact factor is a measure of the citations published within a given journal over a fixed time period. Specifically, it reflects the average number of citations for each paper published in a journal during the two preceding years. So:
Where A= total citations in 2014
B= 2014 citations to articles published in 2012-13 (this is a subset of A)
C= number of articles published in 2012-13
D= B/C = 2014 impact factor
Note that new journals need to wait 2 years before they can be evaluated and given an impact factor [there are some occasional exceptions to this, where impact factors based on partial data will be given].
There can be factors that influence the impact factor, such as the publication of review articles (which naturally tend to include higher levels of citations to earlier literature).
Self-citation can also influence the metrics, but note that the Journal Selection Process takes this into consideration, and artificially high levels of deliberate self-citation will affect the selection process.
Does the journal need to be in English?
As the majority of leading scientific journals are published in English, there is emphasis on English-language publications. There are examples of journals which only publish abstracts and references in English and the main text in another language, but these are in the minority. All journals need to carry their references/bibliographic information in the ‘Roman’ alphabet.
In fact, there is more flexibility within Social Sciences, where local-language publications are important because of reflecting the context of the regional or linguistic areas of study.
It is interesting to note that Web of Science is actively encouraging further submission of regional journals for evaluation, to complement the international coverage that it has traditionally included.
Although it was published a few years ago (Jun 2011), http://wokinfo.com/media/pdf/globalwos-essay.pdf [accessed 4 May 2016], The Globalization of Web of Science, 2005-2010 by James Testa contains more detail on how the coverage of regional journals has increased over time, and this trend is expected to continue.