Introduction: Bibliometrics is a science which evaluates the impact of the scientific work of a journal or of an author, using mathematical and statistical tools. Impact Factor (IF) is the first bibliometric parameter created, and after it many others have been progressively conceived in order to go beyond its limits. Currently bibliometric indexes are used for academic purposes, among them to evaluate the eligibility of a researcher to compete for the National Scientific Qualification, in order to access to competitive exams to become professor.
Objective: Aim of this study is to identify the most relevant bibliometric indexes and to summarized their characteristics.
Methods: A revision of bibliometric indexes as been conducted, starting from the classic ones and completing with the most recent ones.
Results: The two most used bibliometric indexes are the IF, which measures the scientific impact of a periodical and bases on Web of Science citation database, and the h-index, which measures the impact of the scientific work of a researcher, basing on Scopus database. Besides them other indexes have been created more recently, such as the SCImago Journal Rank Indicator (SJR), the Source Normalised Impact per Paper (SNIP) and the CiteScore index. They are all based on Scopus database and evaluate, in different ways, the citational impact of a periodic. The i10-index instead is provided from Google Scholar database and allows to evaluate the impact of the scientific production of a researcher. Recently two softwares have been introduced: the first one, Publish or Perish, allows to evaluate the scientific work of a researcher, through the assessment of many indexes; the second one, Altmetric, measure the use in the Web of the academic papers, instead of measuring citations, by means of alternative metrics respect to the traditional ones.
Conclusions: Each analized index shows advantages but also criticalities. Therefore the combined use of more than one indexes, citational and not, should be preferred, in order to correctly evaluate the work of reserchers and to finally improve the quality and the development of scientific research.
Keywords: Bibliometrics; Google Scholar; H-index; Impact factor; National Scientific Qualification; New metrics; Peer review; PoP; SJR; SNIP; Scopus; Webmetrics; Wos.