Because impact factors vary among disciplines, one cannot meaningfully compare two journals in different disciplines using impact factors. For this reason, it is helpful to see how a journal ranks based on other journals in the subject category.
First find the journal to see what discipline or subject category/categories it falls within. Then find the total number of journals in the subject area. Subtract the ranking of the journal from the total number of journals and divide by the number of journals in the subject area minus 1. Thus you will find the percentile ranking.
Formula: n=number of journals in the subject category
n-rank/n-1 x 100 =percentile 1
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1. Source
Journal Impact Factors
Journal Impact Factor is from Journal Citation Report (JCR), a product of Thomson ISI (Institute for Scientific Information). JCR provides quantitative tools for evaluating journals. The impact factor is one of these; it is a measure of the frequency with which the "average article" in a journal has been cited in a given period of time http://www.sciencegateway.org/impact/
The Journal Citation Reports® tutorial provides an overview of the product and how to use it in your research. http://scientific.thomson.com/tutorials/jcr4/
Science Watch provides ranking and impact factor for a selection of journals, http://www.sciencegateway.org/rank/index.html, and also includes a listing of high impact institutions.
Publish or Perish: Do It Yourself
This is a FREE software program that retrieves and analyses academic citations using Google Scholar cited data. Calculations include Egghe's g-index and the Hirsch h-index. It is more suitable in the areas of business, administration, finance & economics, engineering, computer science & mathematics and social sciences, arts & humanities. The Publish or Perish software can also be installed and used on Apple Mac OS X and GNU/Linux computers, with the aid of a suitable emulator such as Wine or CrossOver Mac.
Please refer to the following pages for detailed download and installation instructions:
The h-index - Developed by Hirsch in 2005, this index is based on a list of publications ranked in descending order by the Times Cited. The value of h is equal to the number of papers (N) in the list that have N or more citations.
The g-index - Introduced by Egghe in 2006, is a well-known index for measuring and comparing the output of scientific researchers, as an improvement of the Hirsch-index.