Intrinsically factor is a free academic site to determine the impact factors of scientific journals using the mutual citations of articles.

The website, launched March 18, 2007 online and is supported by Bergstrom Laboratory of the Department of Biology at the University of Washington. As a free quote is intrinsically factor an alternative to fee-based impact factor of the Journal Citation Reports published by Thomson Scientific (formerly the Institute for Scientific Information ) offer.


In contrast to Thomson Scientific Impact Factor intrinsically factor journals evaluated similarly as Google values ​​websites. Google uses hyperlinks to find a relevance. Eigenfactor uses citations from journals to identify the most influential journals, and draws on the journals of the 7000 Journal Citation Reports, but also uses more than 115,000 additional references from newspapers, magazines and other sources. Eigenfactor recognizing the varying citation standards and time scales of various scientific disciplines. Citations from journals with a higher impact factor is in this case more weight than awarded citations from journals with a lower impact factor. The Zitationsentwicklung followed over five years.

In addition to self factor also offer Google Scholar and citebase alternative, Internet-based forms of citation analysis.