Table 2—

Definition of bibliometric terms employed

TermDefinition
Productivity indexLogarithm of the number of documents published.
Citation indexAlphabetical list, by first author, of items cited in references of a source article.
Impact factor of a journalAverage number of times articles published in the 2 previous years are cited in the current year.
Expected citations in a journalNumber of articles published by a magazine in a year multiplied by the impact factor of the magazine for that year.
Total expected citationSum of the expected citations in all journals.
Expected visibility indexLogarithm of the total expected citations.
Expected impact factorQuotient between the total of expected citations and the number of documents.
Relative impact factorQuotient between the expected impact factor of a country and the mean expected impact factor of the European Union.
Cited half-lifeNumber of journal publication years going back from the current year which account for 50% of the total citations received by the cited journal in the current year
Immediacy indexAverage number of times current articles in a specific journal were cited during the year they were published
Self-citation rateSelf-citations (when an article in a journal cites another article published in the same journal) expressed as a percentage of all citations