Technical details

Jfactor uses the same calculation method as Thomson Reuters impact factor*.

For example,

A = 2014 impact factor for journal X

B = 2014 citations to articles published by journal X in 2012 and 2013

C = total number of articles published by journal X in 2012 and 2013

A = B/C

Below we describe how data are collected to compute Jfactor.

Jfactor data - collection

Publication data

We use INSPIRE's OAI-PMH interface to collect publication information. This consists of XML files that we parse and transfer to an internal DB. There are roughly 1.2 mln records.

References

References are collected with a heuristic process directly from the PDF files of the articles. As they are difficult to extract from the XML files. INSPIRE staff provides us with a json file as needed. This file is also parsed and the information transferred to an internal DB. There are roughly 16 mln references.

Jfactor data - sample

A table showing the latest data collected can be downloaded here.

There is a row for each year and each row contains 5 data points for each journal. Where known, the following are provided:

  1. number of publications in the previous two years (source: INSPIRE)
  2. number of citations of the above in the the current year (source: INSPIRE)
  3. Jfactor
  4. number of publications in the previous two years (source: publisher's web site)
  5. Thomson Reuters impact factor

Contact

For more information and any other requests please contact jfactor@medialab.sissa.it.

*2015 Journal Citation ReportsĀ® (Thomson Reuters, 2015).


Last modified: Fri Jun 19 13:03:45 CEST 2015