Metric
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What it measures
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Strength
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Weakness
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Scholarly output
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Shows total number of outputs published
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Can be used for an individual, group or institution
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Measures productivity rather than impact
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Citation count (of a publication)
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Number of times an output has been cited by others
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Easy to measure using sources such as Web of Science, Scopus and Google Scholar
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Will be lower for papers published more recently.
Doesn’t take account of negative citations or gaming
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Cited publications
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The ‘citability’ of a set of publications: how
many of this entity’s publications have received at least 1 citation?
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Easy to measure using sources such as Web of Science, Scopus and Google Scholar
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Will be lower for papers published more recently.
Doesn’t take account of negative citations or gaming
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Number of citing countries
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The number of distinct countries have that an entity’s publications have received citations
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Indicates the geographical
visibility of an entity’s publications
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Field-weighted citation impact (SciVal)
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The ratio of citations received relative to the expected world average for the subject field, publication type and publication year.
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Shows how the citations received by an entity’s publications compare with the world average
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H-index
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A meeting of productivity (Scholarly Output) and citation impact (Citation Count) of an entity’s publications.
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Easy to measure using sources such as Web of Science, Scopus and Google Scholar.
A single number determines score
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Varies according to data source used.
Ignores small numbers of highly cited papers.
Will be lower for papers published more recently.
Doesn’t take account of negative citations or gaming
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Collaboration
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The extent to which an entity’s publications have international, national, or institutional co-authorship, and single authorship.
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Gives an insight into whether collaboration in a discipline will enhance impact
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Relies on the assumption that past collaborations will remain beneficial
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Collaboration impact
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The citation impact of an entity’s
publications with particular types of geographical collaboration
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Shows how many citations an entity’s
internationally, nationally, or institutionally co-authored publications receive, as well as those with a
single author
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Academic-corporate collaboration
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The citation impact of an entity’s publications with or without both academic and corporate
affiliations
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Gives an insight into whether commercial collaboration in a discipline will enhance impact
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Academic-corporate collaboration impact
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The citation impact of an entity’s
publications with particular types of corporate collaboration
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Shows how many citations an entity’s publications receive when they list both academic and corporate affiliations, versus when they do not
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Altmetric attention score
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An indicator of the amount of attention that an output has received.
The score is a weighted count derived from an automated algorithm, and represents a weighted count of the amount of attention picked up in each type of source, (e.g. score is higher for news items than tweets)
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Measures the attention that an output receives, without it needing to be cited in academic journals. Shorter lead time than traditional metrics.
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Measures attention, not quality. Only tracks public attention. No discipline adjustment added.
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Views per output
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Number of times an output has been accessed online
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Doesn’t rely on output being cited – shorter lead time
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Cannot prove that output has actually been read
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Downloads per output
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Number of times an output has been downloaded online
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Doesn’t rely on output being cited – shorter lead time
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Cannot prove that output has actually been read
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Publications in top journal percentiles
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Indicates the extent to which an entity’s publications are present in the most-cited journals in the
data universe: how many publications are in the top 1%, 5%, 10% or 25% of the most-cited
journals ?
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Arguably indicates the ‘academic impact’
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Assumes that publication in ‘high impact’ journals is synonymous with quality
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Journal Impact Factor
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The average number of times articles from the journal published in the past two years have been cited in the Journal Citation Reports (JCR) year. The Impact Factor is calculated by dividing the number of citations in the JCR year by the total number of articles published in the two previous years.
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Arguably indicates the ‘academic impact’. Measures Journal level impact
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Assumes that publication in ‘high impact’ journals is synonymous with quality.
Article level impact is not measured.
Score can be skewed by a single highly-cited paper [view JIF over a period of years to check that a high JIF is norm and not anomaly]
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SJR (SCImago Journal Ranking)
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A measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from.
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Arguably indicates the ‘academic impact’. Measures Journal level impact
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Assumes that publication in ‘high impact’ journals is synonymous with quality.
Article level impact is not measured.
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SNIP (Source Normalised Impact per Paper) - Elsevier
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Measures contextual citation impact by weighting citations based on the total number of citations in a subject field.
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Adjusts disciplinary differences and offers a normalised benchmark
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IPP (Impact per Publication)
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Measures the ratio of citations in a year (Y) to scholarly papers published in the three previous years (Y-1, Y-2, Y-3) divided by the number of scholarly papers published in those same years (Y-1, Y-2, Y-3).
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Uses a citation window of three years which is considered to be the optimal time period to accurately measure citations in most subject fields.
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Not normalised for the subject field and therefore gives a raw indication of the average number of citation a publication published in the journal will likely receive. When normalised for the citations in the subject field, the raw Impact per Publication becomes the Source Normalised Impact per Paper (SNIP).
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Eigenfactor
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Rating of the total importance of a scientific journal. Journals are rated according to the number of incoming citations, with citations from highly ranked journals weighted to make a larger contribution to the eigenfactor than those from poorly ranked journals.
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Thought to be more robust than the impact factor metric,which purely counts incoming citations without considering the significance of those citations. For a given number of citations, citations from more significant journals will result in a higher Eigenfactor score.
Originally Eigenfactor scores were measures of a journal's importance; it has been extended to author-level. It can also be used in combination with the h-index to evaluate the work of individual scientists.
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Assumes that publication in ‘high impact’ journals is synonymous with quality.
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