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Publishing metrics

The range of models used to measure the impact of journals and articles is constantly increasing, though most are based on the level of citations. As a signatory to DORA, the Royal Society offers a variety of journal and article-based metrics.

Impact factor

The impact factor is a measure of how often an average article in a journal has been cited. It is calculated by dividing the number of current year citations to source items published in that journal during the previous 2 years.

While the impact factor is a relatively easy measure to calculate and understand, it does have some limitations. Given the highly skewed nature of the citation distribution of a journal's articles, the appropriateness of using a mean has been questioned. Also, most journals contain a significant proportion of articles that are never cited. Such articles can be seen as ‘benefiting’ unfairly from the impact factor of the journal in which they appear.

Journal 2020 Impact Factor Rank 5 Year Impact Factor Cited Half-Life Immediacy Index
Proceedings A 2.704 37th out of 73 in ‘Multidisciplinary Sciences’ 3.148 20.14 0.658
Proceedings B 5.349 13th out of 93 in ‘Biology’ 5.977 9.9 1.015
Philosophical Transactions A 4.226 18th out of 73 in ‘Multidisciplinary Sciences’ 4.542 9.6 2.106
Philosophical Transactions B 6.237 9th out of 93 in ‘Biology’ 7.828 9.7 2.887
Interface 4.118 19th out of 73 in ‘Multidisciplinary Sciences’ 4.523 6.4 0.836
Biology Letters 3.703 28th out of 93 in ‘Biology’ 4.228 7.5 0.815
Interface Focus 3.906 26th out of 93 in ‘Biology’ 4.427 4.8 1.96
Open Biology 6.411 58th out of 298 in ‘Biochemistry and Molecular Biology’ 5.898 3.5 0.71
Royal Society Open Science 2.963 28th out of 73 in ‘Multidisciplinary Sciences’ 3.44 2.5 0.665
  • 5 year impact factor: is the impact factor calculated using a base of 5 years’ worth of cited articles, rather than 2. This gives a fairer picture of journals in fields with slower citation patterns, such as mathematics.
  • Cited half-life: the number of years, counting back from the current year, which account for half the total citations received by the cited journal in the current year. This provides a measure of how ‘long-lived’ the articles are in terms of their influence on the literature.
  • Immediacy index: the average number of times that an article is cited in the same year it is published. It gives an indication of how topical the material in the journal is.


The Eigenfactor gives an indication of the overall contribution of the journal, as a whole, to the literature.

It does this using an algorithm similar to that of Google's ‘PageRank’ to count citations into and out of the journal and to weight them according to the ranking of the source or destination. It uses the Thomson Reuters journal dataset and it is intended to measure how likely a journal is to be used or the amount of time a reader will spend reading it. Large journals rank more highly in the Eigenfactor system than small journals (in contrast to the impact factor, which is independent of size).

Journal 2020 Eigenfactor Eigenfactor Rank Article Influence Article Influence Rank
Proceedings A 0.01533 15th out of 71 in ‘Multidisciplinary Sciences’ 1.094 18th out of 71 in ‘Multidisciplinary Sciences’
Proceedings B 0.06107 3rd out of 93 in ‘Biology’ 2.071 10th out of 93 in ‘Biology’
Philosophical Transactions A 0.0254 11th out of 71 in ‘Multidisciplinary Sciences’ 1.406 15th out of 71 in ‘Multidisciplinary Sciences’
Philosophical Transactions B 0.05573 4th out of 93 in ‘Biology’ 2.656 8th out of 93 in ‘Biology’
Interface 0.00448 12th out of 71 in ‘Multidisciplinary Sciences’ 1.513 12th out of 71 in ‘Multidisciplinary Sciences’
Biology Letters 0.01623 11th out of 93 in ‘Biology’ 1.309 17th out of 93 in ‘Biology’
Interface Focus 0.02201 27th out of 93 in 'Biology' 1.237 18th out of 93 in ‘Biology’
Open Biology 0.01028 104th out of 297 in ‘Biochemistry and Molecular Biology’ 1.542 59th out of 297 in ‘Biochemistry and Molecular Biology’
Royal Society Open Science 0.03099 13th out of 71 in ‘Multidisciplinary Sciences’ 0.915 21st out 71 in ‘Multidisciplinary Sciences’
  • Article influence: measures the relative importance of the journal on a per-article basis. It is the journal's Eigenfactor Score divided by the fraction of articles published by the journal. That fraction is normalised so that the sum total of articles from all journals is 1. The mean Article Influence Score is 1.00. A score greater than 1.00 indicates that each article in the journal has above-average influence. A score less than 1.00 indicates that each article in the journal has below-average influence.

Scopus metrics

Journal 2020 CiteScore Scopus Rank SNIP
Proceedings A 4.5 22nd out of 378 in ‘Mathematics’ 1.474
Proceedings B 7.5 12th out of 209 in ‘Agricultural and Biological Sciences’ 1.688
Philosophical Transactions A 6.9 7th out of 378 in ‘Mathematics' 1.475
Philosophical Transactions B 10.9 7th out of 209 in ‘Agricultural and Biological Sciences’ 1.914
Interface 6.6 17th out of 131 in ‘Biophysics’ 1.709
Biology Letters 5.0 22nd out of 209 in ‘Agricultural and Biological Sciences’ 1.177
Interface Focus 7.3 13th out of 131 in 'Biophysics' 1.222
Open Biology 8.4 25th out of 204 in ‘Biochemistry, Genetics and Molecular Biology’ 1.477
Royal Society Open Science 4.9 10th out of 110 in ‘Multidisciplinary’ 1.187
  • CiteScore: Very much like the Impact Factor except that it is based on the larger Scopus dataset and uses 3 years of data. It is the number of citations received by a journal in one year to documents published in the three previous years, divided by the number of documents indexed in Scopus published in those same three years.
  • Source Normalized Impact per Paper (SNIP): Measures contextual citation impact by weighting citations based on the total number of citations in a subject field. The impact of a single citation is given higher value in subject areas where citations are less likely, and vice versa.


Altmetrics are non-traditional metrics proposed as an alternative to citation impact metrics.

We use a partner organisation called Altmetric to track and display the online activity around an article. Altmetric track social media sites, newspapers and magazines for mentions of each published article. The aim is to help authors quantify the attention their article is receiving and to help readers establish the articles their peers think are interesting.

The Altmetric ‘doughnut’ can be found on the ‘Details’ tab of each article.


Publication times

We provide information on publication times, which are regularly updated.

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