For evaluation purposes, as well as for comparison of authors' scientific output, various parameters are used. Among the most popular are:

• number of publications - the basic measure indicating the scientific productivity of the researcher; the parameter is used for further analysis, it can be given in several aspects, as the number of total publications (total), for works affiliated with a particular scientific institution, for a specific database (Scopus or Web of Science), according to the scoring lists of the Ministry of Science and Higher Education (MNiSW)
• number of authors - a parameter for identifying the authors of a publication, useful in co-authorship analyses
• total number of citations
• average number of citations per publication (citation per publication)
• Hirsch index (h-index) - the parameter refers to the total output of an author, determines his average citability, indicates authors who regularly publish highly cited works; h-index is determined by ranking articles by the number of citations and selecting the one for which the number of citations is greater than or equal to its ordinal number. Nowadays, the major citation listing databases calculate this value automatically. It should be remembered that the h-index is calculated for a specific database (based only on those publications that are indexed in it).