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
2016 Journal Citation Reports (JCR) (Clarivate Analytics)
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7.8 |
5-year impact factor: is the impact factor calculated using a base of 5 years' worth of cited articles, rather than 2 years. This gives a fairer picture of journals in fields with slower citation patterns, such as mathematics.
Immediacy index: the average number of times that an article is cited in the same year it is published.
Cited half-life: the number of years, counting back from the current year, that 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.
Citation distribution: the distribution of citations to articles over the previous 2 years that contributes to the current year’s impact factor.
Eigenfactor
2016 rankings
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0.06960 |
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2.862 |
Eigenfactor: a measure of the number of times articles from the journal have been cited in the JCR year. It is a ratio of the number of citations to total number of articles but unlike Impact Factor, it counts citations in both science and the social sciences, it eliminates self-citations (citations of articles published in the same journal) and weights each reference according to the amount of time spent reading that article. The scores are weighted so the sum Eigenfactor scores from all journals in JCR is 100.
Article influence: a measure of the average influence per article of papers in the journal in the first five years of publication. It is the journal's Eigenfactor score divided by the fraction of articles in the JCR that were published by the journal. That fraction is normalised so that the mean Article Influence Score in the entire Thomson JCR database is equal to 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.
2016 ranking
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The SCImago Journal Rank: very much like the Eigenfactor except that it is based on the larger Scopus dataset. It expresses the average number of weighted citations received in the selected year by the documents published in the selected journal in the three previous years, i.e. weighted citations received in year x to documents published in the journal in years (x-1), (x-2) and (x-3).
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.
Article usage metrics
We collect article usage statistics on a daily basis and display them on each article within the ‘Info & Metrics’ tab. The statistics comprise the number of times an article abstract, full-text and PDF view is loaded by a user from individual journal websites.
Note that all articles have zero usage upon publication and the latest available metrics will be displayed 24 hours after they have been collected.
Altmetrics
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 ‘Info & Metrics’ tab of each article.
