Bibliometrics & Responsible Research Evaluation: Metrics Defined
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Research Metrics
There are a variety of research metrics available in different databases. Below are simple explanations of a selection of key metrics and the databases they are available in.
Author Level Metrics
Publication Count per Author
Total number of publications by an author during a time frame.
This measure can be biased against anyone who started publishing later, took a career break, or time off for other reasons. It also biases against those disciplines where publishing is not based on journal articles or conferences.
Due to the weaknesses of this measure, many funders will not allow it's inclusion in applications (e.g. SFI).
Available in Scopus, SciVal, Web of Science and Google Scholar.
Citation Count per Author
Total number of citations an author has received for all of their work over a specific timeframe.
The main weakness of this measure is that if any of the articles included in the set have a significantly different amount of citations compared to the rest of the set, the final citation count will not be a good reflection of the total set of publications.
Available in Scopus, SciVal, Web of Science and Google Scholar.
Field Weighted Citation Impact per Author
Field Weighted Citation Impact is calculated using the ratio of citations received by an individual author, relative to the expected world average for the subject field, publication type and publication year.
This metric is best used for authors with publications of 100 or more. This is because, in smaller publication sets the number can be easily skewed by outliers (e.g. inclusion of an item with say 1,000 citations in a publication set with a most other articles receiving a much lower citation rate).
Available in SciVal and Scopus.
h-Index
The value of the h-index refers to the number of outputs, h, in a bibliography that have each been cited by at least h other outputs. For example, an author claiming an h-index of 20 must be able to demonstrate 20 papers that have been cited 20 or more times each.
This is calculated based on an entire publication record, therefore researchers at different career stages, should not be compared using this. The h5-index was developed to help prevent unfair comparisons. It is calculated using just the last 5 years.
Due to the questionable vaildity of the measure, many funders will not allow the inclusion of the h-index in applications (e.g. SFI).
Available in Scopus, Web of Science, SciVal and Google Scholar.
Article Level Metrics
Citation Count per Article
Number of citations a publication receives during a specific time window.
Available in Scopus, SciVal, Web of Science, and Google Scholar.
Field Weighted Citation Impact per Article
Field-Weighted Citation Impact (FWCI) is the ratio of the actual number of citations received by an output to date and the `expected’ number for an output with similar characteristics. `Expected’ refers to average citations (over the previous three years) for all outputs of the same age, document type and field. Where a journal appears in more than one field category, each field contributes equally to the calculation.
For example a FWCI of 1 for a paper would indicate it is at the world average. One with a FWCI of 2.25 is 125% higher than the world average citation rate.
Available in Scopus and SciVal.
Article Ranking in Topic
Article ranking in this section is a method of searching by topic and then sorting the results by citation count. A specific article can then be manually identified as being within a certain percentage range.
Available in Scopus and Web of Science.
Journal Level Metrics
Journal Impact Factor (JIF)
Journal Impact Factor (JIF) is calculated by the average number of times all articles and reviews from the journal published over a recent three year period have been cited in the Journal Citation Reports year.
The best use for this metric is to look at previous publication history and plan a publication strategy.
It is never to be assumed that an article, published in a highly cited journal, will have higher citation or quality. In their statement on Responsible Metrics UCD explicitly states that this metric will not be used to assess quality. Many funders exclude the use of this metric.
Available in Web of Science and Journal Citation Reports.
Publications in Top Journal Percentiles (PTJB)
PTJP is expressed as the number (or proportion) of outputs which are published in the most heavily cited
journals within a field - irrespective of their individual citation impact. A journal may be in the top 1%, 5%, 10% or 25%.
Like the JIF this measure is appropriate to review and refine a publication strategy.
This metric should never be used to indicate that an article has a high impact, as it only relates to the journal.
There are three different calculations of this available from Scopus/SciVal, CiteScore, SJR, and SNIP. It is best to test each option to explore which is most appropriate.
Available from Scopus and SciVal.