Method for comparison of the number of citations from papers in different databases

Citation analysis has been used to compare researchers, fields, institutions and countries. However, not much has been done to compare citations of papers belonging to different databases and published in different years. This comparison could play a relevant role in many systematic literature reviews concerned with the growth, development, and changes of a particular scientific subject. This study aims to examine whether we can use the percentile approach to compare the number of citations from papers in different databases. We argue that this method can convert citations from different databases when there are same articles belonging to more than one database. We apply the method on Thomson Reuters' Web of Science and Elsevier's Scopus databases because they are the leading databases of scholarly impact. In this study we use two different Scopus subject area: Engineering - Industrial and Manufacturing Engineering; and Arts and Humanities -Archaeology. The analysis comprises articles published for the time period 1987-2017, of journals in the Scopus top 10%, corresponding to approximately 152,000 papers.