?Why are there differences in metrics between databases for the same journal

An article's / author's/ journal's metrics will vary between databases as they will reflect how the article is being cited .within that database. As each database indexes a different range of titles, it is expected that the scores will vary
 

A multidisciplinary journal title's metric may have several metrics reflecting it's standing within the different subject categories it covers e.g. a sports science journal which falls under both Health Professions (Physical therapy, Sports Therapy & Rehabilitation Sports Science) and Medicine ... could receive a different SJR, CiteScore or Impact Factor for each subject category
 

Different types of metrics may be used by different databases, with each database using their own trademarked

metrics. The database will generally provide information as to how the metrics are calculated

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?What is h-Index

An author's h-index attempts to measure both the productivity and citation impact of the publications of a scientist or scholar. The h-index is based on the highest number of papers included that have had at least the same number of citations. For for example a h-index of 5 would indicate that at least 5 publications have received 5 citations or more.

A journal's h-index attempts to measure both the productivity and citation impact of the publications ... the journal's number of articles (h) that have received at least (h) citations. It is best used to compare journals within a discipline as it does not take into account differing citation practices across disciplines (unlike the weighted SJR and SNIP).

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?What is a Field-Weighted Citation Impact  metric
The Field-Weighted Citation Impact (FWCI) is the ratio of citations received relative to the expected world average for the subject field, publication type and publication year. This metric is available in the SciVal database.

A Field-Weighted Citation Impact of 1.00

indicates that the publication has been cited at world average for similar publications
 
A Field-Weighted Citation Impact of >1.00
indicates that the publication has been cited more than the would be expected based on the world average for similar publications. For example, a score of 1.38 means that the outputs have been cited 38% more times than expected
 
A Field-Weighted Citation Impact of <1.00 
indicates that the publication has been cited less than the would be expected based on the world average for similar publications. For example, a score of 0.90 means that the outputs have been cited10% less times than expected.

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