Clients often approach the Scientific Publications Company asking why the quartile indicators in Scimago and Scopus differ? We decided to cover this in detail to help our researchers better navigate this subject area.
Whenever we mention the quartile of a journal included in Scopus, we imply the SJR indicator (Scimago), but one needs to understand that data on the quartile can also be found on the official Scopus website. First, let us consider what Scopus and Scimago are.
Scopus is a database of research abstracts and citations, as well as a source of tools for the analytical work of researchers, scientific publications around the world. The information located in this service is constantly updated and helps find data on financing, make strategic decisions, provides access to relevant information and trends in the subject area, including many other opportunities. Scopus is not publicly available. All platform tools can be used to only after purchasing full access, although certain information can be obtained free of charge.
Scimago is a public service that lists scientific journals and publication rates by countries. Developers take data from Scopus. This information can also be used by researchers for comparison and analysis. Scimago demonstrates the activities of journals included in the Scopus database since 1996.
What are the calculation methods in these two platforms?
Both platforms use particular metrics to calculate log impact. The main metric in Scimago is SJR, in Scopus — CiteScore. Common to both platforms is the presence of information about the quartile of the publication, but frequently it may not match in both services.
SCOPUS
Before CiteScore, Scopus had such metrics as SNIP (Source Normalized Impact per Paper) and SJR (SCImago Journal Rank), which are actively used to this day. But the feedback from users of the platform indicated that a simpler formula is required to calculate the citation metric, so it was decided to introduce a new indicator — CiteScore. It allows evaluating over 20,000 publications, including not only peer-reviewed journals, but also book series, conference proceedings, industry journals in over 300 disciplines. The CiteScore indicator appeared recently, its calculation is quite transparent and understandable. The metric can be independently verified and used with more complex metrics. Indeed, one of the golden rules in scientometrics says that it is always necessary to consider several indicators to evaluate and guarantee objectivity.
How is CiteScore calculated?
Scopus has updated its CiteScore calculation formula. A detailed analysis of the updated methodology is presented in a new video from the Scientific and Educational Centre of the Scientific Publications Company.
SCIMAGO
SJR helps assess the location of the journal, the prestige of scientific articles of researchers, focusing on the number of significant citations for each document. Thus, the journal shares its prestige to other journals by citing articles published in them. A quote with a high SJR has more value than a quote with a lower SJR.
How is SJR calculated?
As the formula above suggests, the method for calculating the SJR is much more complicated than in Scopus.
Why are the data in Scopus and Scimago different?
Since the two platforms use different formulas for calculating the impact of the journal, this difference in indicators arises, as well as differences in these quartiles. CiteScore is based on citation count, while SJR is based on quote weight.
Why is Scopus's CiteScore method more relevant than Scimago's SJR?
SiteScore helps ensure the display of relevant scores across all subject areas. The transparency of this metric allows checking the calculation at any time, which will be based on up-to-date citation information. The formula is devoid of a complex algorithm and simplifies the calculation check.
Apart from CiteScore, users can choose the dynamic metric CiteScore Tracker. It is calculated just as CiteScore, focusing on data based on the current year's performance.
Using Scopus indicators, one can find out the quartile of a journal, as well as anticipate its development by analysing metrics and viewing trends provided by the database. If you are actively applying for grant funding, you need to ensure the development of the journal (so that it does not drop in the rating, but keeps its positions for the next year, for example, Q2 and the article was credited to you if the requirements include Q1–Q2).
Due to the confusing Scimago formula, without an understandable calculation algorithm, it is extremely difficult to take the quartile of the journal into account. The researcher has fewer opportunities to predict the development of the publication and its publication activity.
What should researchers focus on?
Scimago is an affordable platform, unlike Scopus, and easy to understand and use. Therefore, many turn to it when looking for a journal to publish in, etc. But we also recommend that you appeal to the official Scopus service and take information from the primary source, enjoying full use of all the analytical tools offered by the database, building a strategy for your activities.
However, if you notice differences in the indicators of the quartiles of the journal, you must consider the requirements of the platform that is indicated in the legislative documents of your country, as well as depending on the publication requirements of the scientific organisation where you work.
For many years, the Scientific Publications Company has been a guarantee of successful research and publication activities for researchers from different parts of the world. We are interested in our clients receiving qualified support, up-to-date information that will help them publish in high-quality publications and achieve their potential to the fullest. To begin our fruitful cooperation, contact us using the chat on the website. We will be glad to answer your questions!
As a reminder, we have recently published an article “What are the reasons for the delay in the publication of a scientific article?”