The use of a weighted impact factor for the creation of a polythematic list of the most cited journals

The standard impact factor allows one to compare scientific journals only within particular scientific subjects. To overcome this limitation, another indicator of citation, viz., the thematically weighted impact factor (TWIF), is proposed. This indicator allows one to compare journals of various subjects and takes the fact that a journal belongs to several subjects into account. Information on the thematic headings of a journal and the value of a standard impact factor is necessary for calculation of the indicator. The TWIF, which is calculated according to the citation index of Journal Citation Reports, is investigated in this article. © 2011 Allerton Press, Inc.