What is SJR?
The SJR (Scimago Journal Rank) is a metric that measures the prestige and impact of scientific journals. It is based on the concept of prestige transfer via citation links. Developed by the Scimago Lab, the metric ranks journals based on the citations received by their articles and the SJR scores of the citing journals. The SJR metric considers not only the total number of citations but also the quality of the citing journals as the subject field, quality and reputation of the journal have a direct effect on the citation of SJR.
A higher SJR score indicates that a journal has received more citations from other prestigious journals, signifying a higher level of influence and impact within the scientific community. However, the Scimago Journal Rank is just one of many metrics utilised to evaluate the quality and impact of scientific journals, and it should be considered alongside other measures such as the impact factor, h-index, and expert opinion when assessing the significance of a journal.
Why should you utilise SJR?
The Scimago Journal Rank is a public resource, meaning no subscription is needed to access and view any journal’s rank or score. SJR covers all disciplines, taking into account all relevant aspects of a journal tailored to the subject area. Moreover, the rankings are optimised to factor in the differences in citation behaviour between disciplines. It can be argued that SJR is a well-rounded metric, here are some key benefits of utilising it:
- Evaluate journal quality
SJR provides a quantitative measure of the prestige and impact of scientific journals. The score considers both the number of citations received by a journal and the quality of the citing journal. By utilising SJR, you can easily assess the relative importance and influence of different journals within a discipline.
- Identify influential journals
SJR scores journals based on their impact and visibility within the scientific community. The score can identify the most influential journals in your area of research, allowing you to target your publications to maximise their impact and reach.
- Compare journals within a field
SJR provides a comprehensive comparison of different journals within a discipline. You can assess the standing and ranks of journals based on their SJR scores and determine which ones are more widely recognised by the scientific community.
- Benchmark research output
SJR also provides rankings at national and institutional levels. It can assist in benchmarking the research output of different countries or institutions, enabling you to assess their scientific productivity.
- Stay updated on scientific trends
By regularly consulting SJR, you can keep track of the evolving landscape of scientific journals, including emerging journals, new research areas, and trends within your field of interest.
How is SJR calculated?
The SJR (Scimago Journal Rank) is calculated using a methodology that counts the number of citations a journal receives. The source of citations is also taken into account; citations from prestigious citing journals. The steps involved in calculating the SJR score are:
- Collection of data: The methodology is initiated by collecting data on citations from Scopus, which is a comprehensive bibliographic database of scientific literature.
- Weighting citations: Each citation received by an article within the journal is weighted based on the importance of the citing journal. The methodology considers the SJR of the citing journal as an indicator of its prestige. Higher-ranked journals contribute more to the SJR score of the journal being evaluated.
- Normalisation: To account for differences in citation practices between fields of study, the SJR algorithm implements a normalisation process. This process adjusts variations in citation patterns and citation potential across different disciplines.
- Prestige of the citing journals: Journals that receive citations from more prestigious and influential journals are given higher weight in the calculation.
- Journal self-citations: Self-citations, which are citations made by a journal to its own articles, are excluded from the SJR calculation. This ensures that self-referencing does not influence a journal’s SJR score.
- Iterative calculation: The Scimago Journal Rank is calculated iteratively, taking into account the rank scores of the citing journals. This iterative process helps adjust the scores and establish a relative ranking of journals within specific subject categories.
What are the limitations of SJR?
While the SJR (Scimago Journal Rank) metric is widely used and provides valuable insights regarding the impact of scientific journals, it is important to consider its limitations. Some of the limitations of the SJR metric are:
- Subjectivity of Journal Rankings
The rankings provided by SJR are based on algorithms that consider citation data and the prestige of citing journals. However, the determination of prestige is subjective and can vary across different research communities or disciplines. The choice of specific journals in the Scopus database can also have biases in the rankings.
- Limited Coverage
SJR relies on the Scopus database for citation data, which may not include all journals across all disciplines. Certain fields or niche journals may be underrepresented in the database, leading to an incomplete representation of the research landscape.
- Focus on Citations
SJR heavily relies on citation data as the primary focus of a journal’s impact. While citations can be a significant unit of measurement, they do not capture other aspects of a journal’s quality, such as editorial standards, scientific rigour, or societal impact. The metric does not assess factors like the published research’s novelty, originality, or practical applicability.
- Time Lag
SJR scores are updated annually, which means there can be a time lag in reflecting the most recent developments and impact of journals. This delay may not capture the immediate influence of newly published research.
- Field Normalisation Challenges
While the Scimago Journal Rank attempts to normalise citations across different fields, variations in citation practices and publishing patterns can still have biases. Certain disciplines may have higher citation rates due to their nature or popularity, leading to potential imbalances in the rankings.
- Limited Transparency
The specific details of the algorithm used to calculate SJR scores, including the weighting and normalisation methods, are proprietary information and not publicly disclosed. This lack of transparency can make it difficult to fully understand and critique the metric.
What is the difference between Scimago Journal Rank and Journal Impact Factor?
The journal impact factor is a measure of the frequency with which the average article in a journal has been cited in a particular year. It is used to measure the importance or rank of a journal by calculating the times its articles are cited. The calculation is based on a two-year period and involves dividing the number of times articles were cited by the number of articles that are citable.
The main differentiating point of SJR and Journal Impact Factor is that the Scimago Journal Rank measures prestige and Journal Impact Factor measures citation impact. Both metrics utilise citations to settle a journal’s score. Moreover, both metrics rely on different databases, SJR relies on Scopus while Journal Impact Factor relies on Journal Citation Reports (JCR), these well-reputed databases assist the algorithms with which each score is decided. Additionally, SJR scores are optimised to compare journals across disciplines while the journal impact factor is not; using this metric you may only compare journals within one discipline.
In conclusion, the Scimago Journal Rank is a valuable metric that determines the prestige of a specific journal. This article explored why as researchers, you should be utilising SJR and how it is calculated while highlighting the metric’s limitations. To help you gain a better understanding, the article also included a brief comparison between the Scimago Journal Rank and Journal Impact Factor. While SJR is arguably a well-rounded metric, it should not be the only method of analysis and should be considered along with other metrics and expert opinions to draw final conclusions about a specific journal.